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Have an option in-car and on the phone app to enable USB and 12V accessory power jack to remain on when parked.


A few cases where this would be handy:

  • My daughter needed to charge her phone
  • My son wanted to charge is Nintendo Switch
  • We have a 12V powered drink cooler and want our drinks to stay cold
  • I want to charge my OneWheel

I really would like a feature in the mobile app where I could tell it to leave the 12V/USB power on until I get back in the car again.



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USB-C High-Power Ports

by Moderator


Provided USB-C style high-power phone charging ports.


(Originally suggested by Clemens, but split off to keep individual features separate)


Implemented on the Model 3 and Y around 2020.  Implemented on the Model S and X with the mid-2021 release.

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Tesla vehicles have two front USB/Data ports. We’ll show how to add more ports and how to relocate ports to a more secure location. (Jun-2020)

Types of Ports

The center console USB ports on most Tesla cars use Type-A.  Tesla switched to Type-C for all Model Y cars, and the Model 3 builds after May-2020. On the Model S and X, the main display, MCU, uses mini-B type USB connectors, which feed via cables to the center console.

USB ports

USB Ports used in Tesla vehicles


More Ports

You may find you’ve run out of front USB ports for all the devices you wish to connect. Some of those devices may include:

  • Direct Phone charger
  • Wireless phone charger
  • Flash drive for music
  • Flash drive for the Tesla dashcam
  • SSD drive for music and/or the Tesla dashcam
  • Dashcam that requires 5v (non-Tesla types)
  • Game controller
  • Console LED lighting

There are at least two ways to get additional ports. For charging, we recommend getting a 12v USB power plug. These are often under $20 and can provide one, two, or more high power USB ports.  The ports in the Tesla are USB 2.0 and can supply about 500 mA.  Most phones made in the last 4+ years offer fast charging, but you need more current.  The 12v USB power plugs are available with 2.4 amps USB ports, which can charge a phone about 5 times faster than the Tesla USB connections.  These higher-power USB ports are also best for wireless charging and other high-power needs.

A USB hub allows for the expansion of a single USB port to multiple ports. The most common hubs expand one port to 4 ports, but there are many other sizes.  An unpowered hub will split the power from the single port to the other ports. This means you have a maximum of 500 mA spread across 4 ports.  For low power devices that can be fine.  For a high power device like an SSD drive, it may not be enough. While they make powered hubs, most of these are intended for 120V power but might be adapted to 12v or 5v.


Port Relocation for Security

Tesla has some great features on newer vehicles such as Sentry mode with dashcam recording. One concern is during a break-in, a knowledgable thief could easily grab the USB drive that holds all the video of the break-in. One solution is to re-route the drive to another hidden or locked location.

For example, relocating the USB connectors to the glove box would be perfect. The glove box is locked when the car is off, so access is far more difficult, yet access is easy if you have the key.  This addresses the issue of a Valet damaging the car and taking the drive, as the glove box is also locked when Valet Mode is active.

There are many ways to accomplish this, and some options are easier than others. We’ll outline several ways to accomplish the move, but you can modify the approach the best fits your needs and effort you wish to expend.

Method 1 – Access the ports on the back of the MCU of the Model S or X

This is the most professional approach, but you’ll likely need to remove much of the dashboard to pull the MCU partly out so you can access the two USB connectors on the back of the MCU.  If this is too difficult for you, look at method 2, which is easier.  We’ll connect a 4-port hub to each of the MCU USB connections.  One hub will connect to the existing two USB port cables that route to the center console. The 2nd hub will connect to two ports mounted in the glovebox.

Parts needed:

The following diagram shows the cables and connections.

Cable connections

Cable connections


Rear of MCU

Rear of MCU

Quite a bit of the dashboard must be removed to get access to the MCU.  This video on removing MCU1 shows the steps required.  MCU1 and MCU2 removal processes are the same.  The back connectors have an unusual locking method for the USBs. If you’re using some standard USB cables, it may not fit. You’ll likely need to trim off some of the plastic on the cable’s Type-B connector to fit into the slot in the back of the MCU.

The closest we could find that perfectly matches the connector in the MCU is a cable from TE, Part Number 1557331, that has the right locking connector, but has another Type-B connector on the other end. It’s also not available and is marked obsolete in the catalog.

Method 2 – Connect to the Center Console

In this method, we connect to one center console connections and run the cable to a hub that feeds two ports in the glove box.

Parts needed:

The following diagram shows the cables and connections for the S/X/3 that uses the larger Type-A USB connectors.

For vehicles with USB Type-A

For the Model S/X, while not necessary, for the Type-A connections, you may want the additional right-angle cable. You remove the console rubber mat and use an existing hole or make a new hole and feed the wire under the area.  There is another rubber mat that lifts out along most of the bottom of the console. Remove it and run the 2nd cable under the mat to the rear of the console and feed it out the back.

The next diagram applies to the 3/Y that has the Type-C connectors.

 For vehicles with USB Type-C

For vehicles with USB Type-C


Thanks go to Akikiki for helping to design this project!

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We have a new site CamMem.com that focuses exclusively on the Tesla Dashcam, including:


Our editors select and review products independently.  Any of these should work great to record Tesla’s dashcam video. Speeds are from the manufacturer for the drive sizes listed. (Aug-2021 update)

Smaller capacity drives (not shown below) are often slower than larger ones. Price categories indicate the rough value of items unless otherwise stated.

Value Indicator Range
$ up to $24.99
$$ $25 to $49.99
$$$ $50 to $99.99
$$$$ $100 and above

SD Cards with Adapter

There are several adapters that convert an SD card for use as a USB stick. This allows the use of micro SD cards, often designed specifically for dashcam video with extended lifetimes and suitable temperature range over other flash drives. In addition, the adapter can be connected to a phone, tablet or PC to view the video.

The adapters listed support a variety of SD card types (we recommend micro SD, but others work as well). They are USB 3.0 and work on both PCs and MACs. The first three work with Android phones that offer OTG and the specified connector. The Difini and SmartQ work with current iPhones (not shown in picture). This allows you to quickly view video files on your phone. Adapters below are shown with caps removed, and I’ve inserted a micro SD card in the side of each adapter. The SanDisk adapter is tiny and only has a single USB connection.

usb adapters

Vendor Value USB Connector Phone
Sabrent 2-Slot Micro USB $ 3.0 Micro USB Android
Vanja USB Type C SD Card Reader $ 3.0 USB Type C Android
SmartQ C350 Type-C USB $ 3.0 USB Type C Android
Difini Micro SD Card Reader $ 3.0 Lightning iPhone 5 to X
SmartQ C618 USB3.0 MFI Lightning $$ 3.0 Lightning iPhone 5 to X
SanDisk MobileMate USB Reader $ 3.0 none no

The adapters above require an SD card, which is sold separately. All of the micro SD cards below are designed for dashcam use and are longer life MLC types.

Vendor Value Category Read/Write Temp
Samsung PRO Endurance 32 GB $ UHS-I U1 100/30 MB/s -13 to 185°F
Samsung PRO Endurance 64 GB $ UHS-I U1 100/30 MB/s -13 to 185°F
Samsung PRO Endurance 128 GB $$ UHS-I U1 100/30 MB/s -13 to 185°F
SanDisk High Endurance 32 GB $ UHS-I U3 100/40 MB/s -13 to 185°F
SanDisk High Endurance 64 GB $ UHS-I U3 100/40 MB/s -13 to 185°F
SanDisk High Endurance 128 GB $$ UHS-I U3 100/40 MB/s -13 to 185°F
SanDisk High Endurance 256 GB $$$ UHS-I U3 100/40 MB/s -13 to 185°F
Transcend High Endurance 32 GB $ UHS-I U1 95/25 MB/s -13 to 185°F
Transcend High Endurance 64 GB $$ UHS-I U1 95/45 MB/s -13 to 185°F
Transcend High Endurance 128 GB $$ UHS-I U1 95/45 MB/s -13 to 185°F

Stick Style Flash Drives

Before V10, Tesla added a performance test and will shut out the drive if too slow. We and others are finding even some seemingly fast drives are being failed by Tesla’s speed test. On closer examination, the drives fail to maintain the write speeds at a sustained rate and can slow down dramatically as the drive fills up.

We’re now recommending using micro SD cards with an adapter, but we list the best stick drives that may work for you. Note the temperature range may be inadequate in your car.

USB flash drive

Vendor Value USB Read/Write Temp
Kingston DataTraveler Elite G2 32 GB $ 3.1 180/70 MB/s 32 to 140°F
Kingston DataTraveler Elite G2 64 GB $$ 3.1 180/70 MB/s 32 to 140°F
Kingston DataTraveler Elite G2 128 GB $$$ 3.1 180/70 MB/s 32 to 140°F
Samsung Bar Plus 64 GB $ 3.1 200/25 MB/s 32 to 140°F
Samsung Bar Plus 128 GB $ 3.1 300/50 MB/s 32 to 140°F
Samsung Bar Plus 256 GB $$ 3.1 300/50 MB/s 32 to 140°F
Samsung MUF-64AB/AM FIT Plus 64GB $ 3.1 200/50 MB/s 32 to 140°F
Samsung MUF-128AB/AM FIT Plus 128 GB $ 3.1 300/60 MB/s 32 to 140°F
Samsung MUF-256AB/AM FIT Plus 256 GB $$ 3.1 300/60 MB/s 32 to 140°F
Transcend JetFlash 780 64 GB $$ 3.0 210/140 MB/s 32 to 158°F
Transcend JetFlash 780 128 GB $$$ 3.0 210/140 MB/s 32 to 158°F
Transcend JetFlash 780 256 GB $$$$ 3.0 210/140 MB/s 32 to 158°F

The price differences are likely due to the type of memory used. We could only confirm the Transcend drive uses MLC memory, which has the best lifetime (and highest price).

Drives that are known not to work reliably in all cars:

Vendor USB Read/Write Temp
SanDisk Extreme Go, 3.1 (all sizes) 3.1 300/50 MB/s 32 to140°F
SanDisk Extreme Pro, 3.1 (all sizes) 3.1 420/380 MB/s 32 to 95°F

SSD Drives

Some owners use an SSD drive with a SATA to USB converter. This should work fine, so long as the SSD drive peak power consumption is under 2W for older S/X or 6.2W on the Model 3/Y or mid-2021 S/X.  Many larger SSDs 256 GB or larger consume more than 2W while writing, and peak consumption is even higher. Even some smaller drives exceed Tesla’s USB power budget. If you exceed the power needed, writes become intermittent and it’s even possible to damage the SSD drive. Here’s one SSD power consumption guide we found, but it does not rate peak power.

SSD drives often have great wear-leveling technology that extends the life of the drive. This technology is not in USB stick type flash drives or SD cards. The downside is the limited temperature range. The drives are intended for use in a home, not a car.

Here are some USB based small packaged SSD drives that are below 6W, and will work fine in many cars.  During writing, the peak power may exceed the power available on the older Model S/X USB 2.0 ports, so it may not work reliably.

ssds for tesla

Vendor Value USB Read/Write Temp
Samsung T5 Portable SSD 500 GB $$$ 3.1 540/540 MB/s Unstated
Samsung T5 Portable SSD 1 TB $$$$ 3.1 540/540 MB/s Unstated
Samsung T5 Portable SSD 2 TB $$$$ 3.1 540/540 MB/s Unstated
SanDisk Extreme Pro Portable 500 GB $$$$ 3.1 1050/500 MB/s 32 to 95°F
SanDisk Extreme Pro Portable 1 TB $$$$ 3.1 1050/500 MB/s 32 to 95°F
SanDisk Extreme Portable 2 TB $$$$ 3.1 550/500 MB/s 32 to 95°F
WD My Passport SSD Portable Storage 512 GB $$$ 3.1 540/300 MB/s Unstated
WD My Passport SSD Portable Storage 1 TB $$$$ 3.1 540/300 MB/s Unstated
WD My Passport SSD Portable Storage 2 TB $$$$ 3.1 540/300 MB/s Unstated

Wireless Connection USB Drive

A few users have purchased the SanDisk Connect Wireless Stick, which acts as a normal flash drive for recording, but when removed and separately powered, it can connect via WiFi to your phone or tablet.

sandisk connect drive

It’s a USB 2.0 drive, that is slow, and may not keep up with the four channels of video streaming. That said, a few owners are using it and haven’t reported issues.

Vendor Value USB Read/Write Temp
SanDisk Connect Wireless Stick 32 GB $$$ 2.0 16/10 MB/s 32 to 113°F
SanDisk Connect Wireless Stick 64 GB $$$$ 2.0 16/10 MB/s 32 to 113°F

TeslaUSB with Raspberry Pi

For the power DIYer, there is the Raspberry Pi or the smaller Raspberry Pi Zero (Paid Links). In combination with the TeslaUSB software, you have a small computer that makes the file system available to a USB port.

Raspberry Pi Board

You can have video files saved for later, getting around the Tesla one-hour limit, or even having the Pi computer auto-upload via WiFi to a home network when you arrive home. The Raspberry Pi uses a micro SD card, which allows for a dashcam grade memory. See our section above on micro SD cards if you go this route.

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USB Adapters and Charging

by Moderator

On the Model S, the USB connections point outwards, making most USB drives stick out like a sore thumb, and may break if anything drops on it.  There are several adapters available that eliminate this concern:

USB 3.0 Male to Female Vertical Left Angled Adapter

USB 3.0 Male to Female Vertical Left Angled Adapter – Available at Fasttech (it’s v2.0 compatible too)

With most cars, including the Tesla Model S, the USB ports are limited to 500 mA per connection.  Quite a few devices charge significantly faster if you have 1000 mA or 2100 mA available. You can check your device’s charger to get a better idea of the desired charge current.  If you are only using the USB port to charge, you may be better off with an adapter that plugs into the 12V cigarette lighter power connector next to the two USB ports.  There are a large number of devices to pick from, including those that handle more than one USB connection.  Below is one product, but there are many more if you search for them.

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Concealed USB Locations

by jcadman22


Add always-on USB charging ports to the glove box, rear hatch, or frunk areas to securely charge devices while away from the car. These do not have a data connection.


I carry my music library around on a portable hard drive which lives in the center console. This leaves a bright blue LED power light visible all the time. More importantly, it consumes 50% of the USB ports for a device that I don’t need convenient access to. With the introduction of data plans, owners may consider leaving a hot spot in the car for wi-fi data access. This would eat up the other USB port leaving none available for driver & passenger phone charging.

Moderator: There are $10 devices that plug into the 12V power jack that can provide one or two high-power charging ports, but this power is turned off when leaving the car.


All new Teslas (as of late 2020) include an additional USB connection in the glove box.  This offers both the ability to charge and use for music or the dashcam feature.

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Make a couple of USB power ports available to the back seat. This is useful for charging and running phones and tablets as entertainment for the back seat passengers on long trips.


A cheap under $20 alternative is getting a USB power plug. Models have one or two USB ports and plug into the 12V accessory port. These usually provide up to one amp per port, for fast charging rates.


As of 2019, rear USB charging ports are provided in all Tesla vehicles.

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Third Row Cooling Console

by Moderator

The optional third-row seats can be a hot place for kids in the summer months. One company offered a custom manufacturing a rear removable console that includes a variable speed fan, two USB power connections and a Phone/LED display mount. As of 2019, it appears this product is no longer made.




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Articles Test

by Moderator

Check out our in-depth articles!  Categories include:

For New Owners • Solar • Analysis • Technology • Audio • Dashcam • Repair • Other

For New Owners


Owner’s Manual Companion

Everything you wanted to know about your new Tesla vehicle, the Tesla forums, and more! (Aug-2020 update)

range university logo

Range University

Understanding what the Range display means and why it may not be accurate (Jun-2020 update)

home charging

Home Charging Wiring Guide

Explains safe wiring methods for charging your Tesla S/X/3/Y at home. (Jul-2020 update)

Model 3 charging

Model 3 Home Charging Guide

Charging speeds, best solutions, outlet choices, and more! (May-2020 update)


Supercharger SuperGuide

Our deep dive into Superchargers – how to speed your charging, how it works and more (Jul-2020 update)

battery pack

Selecting the Right Battery Size

Our handy guide getting the S/X/3 battery that’s best for you! (Nov-2019 update)



Tesla Solar Roof Installation

Our very own Tesla solar roof project with video, costing, and more! (May-2020)

Solar-Powerwall System Optimizations

Tricks to getting more useful power and improving Powerwall longevity (May-2020)


Charging Connector

Supercharging, CCS and CHAdeMO DC Fast Charging

Comparing these three systems and the related networks (Jul-2020 update)


Autopilot, Processors, and Hardware

Demystifying MCU and HW variants (Apr-2020 update)


MCU1 Flash Memory Analysis and Failures

An examination of MCU1’s eMMC memory, failure rates, causes & solutions (Aug-2020 update)

MCU retrofit

MCU2 Upgrade and AM/FM/XM Radio Issues

Options when radios are removed for the MCU2 upgrade (Jul-2020 update)

model varients

Timelines for Vehicles and Variants

Dates of vehicle versions and major changes, EPA range and more (Jul-2020 update)

Paint and Coatings

All about factory and body shop painting, coatings and common myths (Jun-2019 update)

Solar cell

Solar Vehicle Roof Analysis

How much range would a solar roof provide and at what cost? (Oct-2019 update)



12 Volt Battery Compendium

Everything you need to know about your Tesla 12v battery! (Jun-2020 Update)


Understanding New Battery Breakthroughs

Battery breakthroughs may not always work as hoped for in vehicles (Oct-2019 update)


Understanding this critical high-power component (Feb-2019 update)

Processors Analysis and Count

Check out the 50+ processors used in Tesla vehicles (May-2013)



Audio Systems for the Model 3

Our deep dive into speakers, amplifiers and more on the Model 3. (Jun-2019 update)

Speakers and Amps

Audio Systems for the Tesla Model S and Model X

Examination of features, speakers and amplifiers (Aug-2018 update)

XM logo

XM Radio for Tesla

XM availability, options, alternatives and tips (Oct-2019 update)

USB Flash Drives for Music

How to pick the right USB drive for great music and getting the most out of your vehicle’s music system (Oct-2019 Update)


Streaming Audio

Streaming services and getting better streaming sound (Oct-2019 update)

Android Auto

Android Auto on Tesla?

An examination of Google’s Android Auto and what issues may slow or prevent implementation (Oct-2019 update)

carplay logo

CarPlay on Tesla?

An examination of Apple’s CarPlay and what issues may slow or prevent implementation (Oct-2019 update)



USB Flash Drives for Tesla Dashcam

How to pick a reliable drive, setting it up and troubleshooting (Oct-2019 update)


Ultimate 2020 Tesla Dashcam Guide

Exploration of the why what and how of dashcams with comparisons and installation videos (Jan-2020 update)


Repair Cone

Tesla Accident Repair Guide

How to navigate the accident repairs process and timing (Jun-2019 update)

broken window

To Catch A Thief – Tesla Breakins

Breakin, investigation, and tips to avoid a break-in (Jul-2019)

Sounds of Tesla

Sounds of Tesla Vehicles

Normal and abnormal noises and sounds with solutions (Oct-2019 update)


HomeLink Analysis and Troubleshooting

Understanding HomeLink and fixing common issues (Oct-2019)


WiFi Guide and Troubleshooter for Tesla Vehicles

The Why and How of WiFi and how to get the best connection (Oct-2019 update)

paint chip fix

Fixing a Paint Chip

Quick ways to fix small rock strikes and road rash (Oct-2019 update)


VIN Decoder

Learn what your Vehicle Identification Number says about your car (Jul-2020 update)

tesla stores

Maps – EV Benefits, Tesla Stores & Superchargers

View maps of the USA with benefits by state, Tesla stores and service centers and counts of Superchargers (Apr-2019 update)


Model S Changes from 2012 to 2019

We’ve compiled an extensive list of changes over the last 6+ years (Apr-2019)


Old and New Luxury

How luxury is being redefined in vehicles (Aug-2017)



Easy to understand charging options for the Model S/X (Oct-2019 update)

Main Screen V7 User Interface Analysis

Changes from the 6.0 to new 7.0 (Oct-2015)

Instrument Panel

Instrument Panel V7 User Interface Analysis

Changes from the V6.0 to 7.0 (Oct-2015)

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MCU is the 17” display and computer behind the display on the Model S and Model X built prior to 2021. It is used for entertainment, maps, navigation, and HVAC control.  It does not control the ability to drive the car, which means it can be rebooted or fail while driving and is not a safety-critical item.  Inside the MCU is flash memory, like a flash drive you might use to store music or dashcam video. The flash memory used is called eMMC or embedded Multi-Media Chip. Flash memory has a finite lifetime, and at some point, they fail. Some owners have had the MCU1 fail due to the flash memory failing, which can be expensive if it occurs outside of the 4-year, 50,000-mile warranty. Tesla has extended the eMMC in MCU1 warranty to 8 years / 100,000 miles. They also created a reimbursement program for those that had eMMC repairs done within the new warranty period.  More details in the Warranty Adjustment Program.  Even more recently, Tesla initiated a recall to replace the eMMC in MCU1.  More Tesla details at 8GB eMMC Recall Frequently Asked Questions (Sep-2021)


The rear of a removed MCU1


While most cars have never had any MCU problems, some cars have had the MCU1 fail.  The most common failure is the internal flash memory, called eMMC, which is no longer able to reliably store data. When this occurs, owners may see erratic operation of the display, very slow responses, map rendering issues, reboots that occur by itself, reboots that take longer than 5 minutes, or a completely black screen. When totally failed, your phone app and Tesla service cannot remotely access the car.

Due to the way the memory is used, a high percentage of failures occur during a software update.  The update needs to write a lot of data into the flash memory in an unused area. If that area has previously failed, once the update is installed and it switches to that update, the system crashes.  It’s not a bug in the update, but the flash memory not working properly.

There are other possible causes of MCU1 failures, but they appear less frequently.  The 2nd most common issue is the touch operations become erratic and or are ignored completely.  This is usually a fault of the touch controller and a screen replacement corrects it. This is cheaper than having the entire MCU1 replaced.

There are likely a few other rare part failures in the MCU assembly, but for the rest of this article, we are going to only focus on eMMC failures. We also expect some MCU1 failures are not eMMC related, but we assume every reported failure is due to eMMC.

Failure Operation

Tesla has made some modifications to keep some functions operational in the event of failure. With several updates, the last being 2020.48.12, it will maintain defrosting if on, and set the cabin temperature to 72ºF.  In addition, the rear-view camera will appear on the screen.  The updates provide an early warning of eMMC problems, up to 6 months before it will fail.


MCU1 design went into service in July-2012 with the first Model S.  It has been used in both the Model S and X through 28-Feb-2018.  After this, Tesla switched to a new design, called MCU2. During this time, about 317,000 vehicles were made with MCU1.

During the production, there were several minor design changes and one significant change – support of LTE in mid-2015.

In most cases, MCU1 is removed, opened up, and the CPU daughterboard with the eMMC memory is replaced with a daughterboard with a new 64 GB eMMC chip.  This chip is a better design as well, considering it was designed 10 years after the original part.

In some cases, MCU1 is replaced. Replacements are done with a remanufactured unit. The defective unit returned to the factory for repair.  This is a standard practice in the automotive world.  The service technician does not have to identify what internal part may have failed but just swaps out the unit, such as MCU1.  All current remanufactured MCU1s include a different eMMC part that has at least 8 times the longevity of the original part, as the original part is no longer made. 

A replacement MCU1 also includes the LTE feature for no extra cost, a $500 option by itself, should you have an older Model S without LTE.  Note that in the USA, 3G phone service is expected to be terminated by phone carriers by February mid-2021.

Failure Rate

Akikiki has done some amazing work collecting data from owners of failed MCU1s.  This is a combination of reports in the Tesla forums and the TMC forums.  As of January-2021, we have 553 reported failures worldwide. This includes Tesla replacements MCU1s, MCU2 retrofits, eMMC daughterboard replacements, and third-party replacements of the eMMC chips.

Obviously, this is not the entire universe of failures, as not everyone reports problems to the forums.  Still, this is great information that puts a dimension on the issue.  Of the failed MCUs, 2 have not been identified with a vehicle year, and the others shown below have known vehicle years.

Vehicle Year Age (in 2020) MCU1 S/X Sales Failed MCU1s % Failed per year
2012 8 2,650 17 0.080%
2013 7 22,242 100 0.064%
2014 6 31,655 71 0.037%
2015 5 51,773 219 0.085%
2016 4 75,890 98 0.032%
2017 3 103,020 44 0.014%
2018 2 29,980 4 0.007%

The average failure rate per year is 0.046%.  We know this is not the entire universe of failures, as we expect plenty of people do not report failures in the forums.  Before we multiplied this by 15, but we now think there are more failures we don’t know about and increase this value to 25.  This is a bit of a guess, but we are saying our numbers only include 1/25 of the actual failures.

0.046% * 25 = 1.15% per year estimated failure rate.

Now we also have some data from Tesla: “Tesla said it has received 2,399 complaints and field reports, 7,777 warranty claims, and 4,746 non-warranty claims related to MCU replacements.” The 2,399 number likely overlaps many that had MCU1 fixed, but let’s lump them all together anyway for 14,922 failures.

So total failure over say 5 years is 14922/317,000 = 4.7%. Per year that’s 4.7/5 = 0.94% per year. Tesla’s numbers are very close to our analysis, which was done without any input from Tesla!

Let’s look at the data another way. Here we charted the failure rate for each model year represented by each color. The colored lines represent the vehicle year.  The X-axis, with years prefixed with “F”, is the year the failure rate for that year.

The peak failures occur for a 2012 Model S (in light blue) in 2020, or 8 years after the vehicle was made.  We combined S and X sales in all our numbers, but the Model X sales did not start until V-2015.  We left out a few failures that did not identify the model year or when MCU1 failed.

Now we’ve used the same data but added in some major events, the introduction of AP1 in 2014, AP2 in 2016, and when Linux logging was stopped in late 2019.

It does look like AutoPliot increased the failure rate and removing the Linux logging might have helped. Consider the V-2012 vehicles, shown in the light blue line, do not have AP1 or AP2 yet failures increase sharply in year 6.  For the year 2015 vehicles with AP1, the sharp increase occurs in year 5.  It’s too early to tell the effect of AP2 with 2017 vehicles.

Tesla has also made a number of optimizations to the utilization and management of the eMMC flash memory. Tesla strongly recommends you have version 2020.20 or later to get all these optimizations.  In addition, should the eMMC start to fail, versions at 2020.20 and later will default the CPU into a safe mode that provides defrost, cabin heat/cool, and rear-view display.

So, will your MCU1 fail?  That’s impossible to answer, but we can at least shed some light on some factors that affect the life of the eMMC.

eMMC Longevity and Wear

On the number of cycles before failure, there are many unknown variables, which makes it difficult to predict when a failure may occur or if there is anything you can do to extend its life.  There are many vehicles on the road that are over 7 years old and/or have over 200,000 miles and the MCU1 is still working fine.  On the flip side, there have been a few failures in cars less than 4 years old and less than 30,000 miles. We’ll look at why there can be so much variance in longevity.

The chip itself. There isn’t a hard count limit where a byte fails. It likely varies depending on micro variances in the making of the chip. You could have one chip last it’s rated 3000 cycles and another that lasts 10000 cycles. The manufacturer only specifies the minimum cycle life.

Data Values – You could have a byte fail, but the data written to it happens to match the failure, so it is not yet marked as bad. For example, if a byte fails to all zeros, and you write zero to that location, it is still valid, and no-fault occurs.

Block write – Flash memory writes in a block of bytes. In the SK Hynix eMMC used by Tesla, a block is 448 bytes. The entire block is always written if any byte changes within that block. If after a write, if the block does not match what was written the group is marked bad, and it is re-written into another block. This happens in the background and depends on how many free blocks are available. When the available blocks are exhausted, the chip has nowhere to write the data. What happens at that point is unclear, but you are going to lose data. Later when the CPU attempts to read code or data values from a corrupted section of memory, things can go awry.

Temperature – There are other smaller factors, such as temperatures that are likely to affect longevity. The specs provide a minimum cycle life over the temperature range, but I’d expect longer cycle life at one or the other ends of the temperature range. So if your car always hot or always cold, it might last longer or shorter. I have no idea which way is better or how much effect it has.

Frequency of data change – Code updates are very infrequent and would not cause cycle life failures. I estimate there have been less than 100 code updates since 2012.

Various settings are also stored in the eMMC memory, but those values do not change often.

There are server logs, and some thought this was the cause of early failures. A typical Linux server log is quite small and these changes, while frequent, should last far beyond the life of the car. Others disagree with me, but no one has done an extensive logic-analyzer evaluation. Near the end of 2019, Tesla disabled the internal server log to reduce writes. These logs are only useful for Tesla’s engineers during development.

There are vehicle logs, data such as charging history, and vehicle faults. I don’t know how much data is collected; I don’t expect this is a significant amount of data or that it causes a lot of writes.

There are other items that may be saved, such as streaming audio. I suspect it is saved in RAM, but if some of it is saved in the eMMC, such as the buffered song when downloaded, this is a large amount of memory, about 6 MB for a 3-minute song. The use of streaming varies a lot by the user. Some owners never use it, while others are frequent streamers. More likely the music file is only saved if the MCU is powered off. Probably this is not a concern.

For those that use a USB for music, the songs are indexed and the index is stored in the eMMC. Prior to Version 10 software, the indexing also stored thumbnail album cover images. This may have been a large amount of data for those with a lot of songs.  The data is re-indexed when the USB is disconnected and reconnected, but this occurs infrequently.

Navigation data is saved to flash, but as to how much, it is unclear. Web history is also saved. Some owners may use these features more frequently than others and may increase the number of write cycles. Most of this data seems quite small, so I would not expect it to have much effect.

Some Tesla techs have stated the trip counters consume memory and cause more eMMC use.  While I am sure it uses some memory, I doubt it uses much compared with other items.

AutoPilot has a lot of information that is recorded for operations that did not occur in pre-AP cars. While most of the data is never saved, if even a small fraction is saved, it could be a huge amount with video files or images. There has been talk that AP data is also being saved even if you are not using AP, but perhaps more data is saved when AP is active.  This may be why the year 2015 cars seem to have failures earlier in life than 2012 vehicles.

Memory Controller Design Problem – A few people have suggested there is a design problem in the chip’s memory controller. We cannot substantiate such a problem, but it is always possible. Perhaps the memory controller is creating more writes than is needed, causing excessive wear.  Considering several companies use these parts in volume, I would expect more news about it if were true.

eMMC Parts

Tesla bought the processor board from Nvidia, and the Nvidia board contains the eMMC from SK Hynix. Unlike consumer flash memory, the eMMC is soldered to the PCB via a 153 ball pad array.

A fixer in Europe, reported the following parts being used on the boards:

H26M42001FMR in 2012 and 2013 cars

H26M42002GMR in ~ 2014 cars

H26M42003GMR in 2015+ cars.


These chips are all made by SK Hynix, are 8 GB parts, and are MLC (Multi-Level Cell) design.  The chips include a flash controller to make the memory accessible to software like a disk drive.  We have been unable to find any significant difference between the parts, other than small tweaks to the controller specifications.  We do not believe the different parts would have any functional or longevity differences.

The minimum write cycle life is 3,000 cycles, and data retention is rated at 10 years. The 42001 and 42002 parts adhere to the MMC 4.41 standard and the 42003 part uses the MMC 4.5 standard. In this application, the parts can be considered interchangeable.

Interestingly, we found that the same part, the H26M42003GMR, is used in the Microsoft X-box One.

All three of these parts are considered obsolete now by Hynix and are no longer manufactured.  I was able to find some small inventory of the last two versions for sale, but none of the first versions. There are now larger and better parts available that are functionally the same.

Replacement of the eMMC is quite tricky. First, you need to extract some key information from the chip and transfer the data to a new chip before removal.  Next, you have to remove the eMMC without harming the PCB – an effort that few have the right equipment or skill.  Then with the replacement part pre-loaded with the data extracted from the original chip, you need to solder it to the PCB, again with specialized equipment.

A video of the MCU1 disassembly and eMMC replacement process (courtesy of B1Zteam)

Some third-party vendors are replacing the SK Hynix eMMC with a Swissbit SFEM064GB1EA1 or similar chip formatted to 32 GB for compatibility.  This should last far longer than the original due to its size and pSLC endurance mode, perhaps as much as 28 times longer. This part retails for $67 today.

For replacements done by Tesla, they are using a 64 GB Micron eMMC, and possibly another vendor.

Safety Concerns

Some owners think an MCU failure is a safety concern.  While we don’t’ share that view, if your MCU fails and you consider it unsafe to drive, you should stop driving and have the car towed, and have the MCU1 repaired.

The car drives fine without MCU1 working, but some vehicle features may not work or may work in limited ways.  Some items like exterior turn signals should still work, but you may not get any inside audible confirmation or indication on the screen. The rear camera does not appear when you are in reverse unless you have version 2020.20 or later software.

There have been some owners reporting an MCU1 failure as a safety item to the NHTSB due to the lack of a rear camera video. Rear camera video is only required on all cars made starting in May 2018.  More details on the NHTSB Model S, under investigation.

Since a rear video camera was not required until after MCU1 was discontinued by Tesla and replaced by MCU2, it seems unlikely the NHTSB will consider an MCU1 failure a safety concern, but they did. This is even with the change that provides a rearview camera on-screen even if the eMMC fails.  In the past, safety concerns have focused on items that cause an immediate accident, such as a wheel breaking off, an airbag issue or the engine catching fire.


The MCU is covered by the vehicle’s 4-year, 50,000-mile warranty and as of November 2020, Tesla has extended the warranty of the eMMC in MCU1 to 8-year and 100,000 miles.  Now Tesla has implemented a recall on the eMMC, so the warranty period is not important.


Have Tesla fix it.  There is no cost. This should last at least 8 times longer, and depending on the chip design, perhaps a lot longer. 

There are alternative vendors that can take your MCU1 and replace the bad eMMC part. These were useful when Tesla was charging for eMMC repairs, but we’ve retained this information, as not all countries may get the recall.

To use these vendors, you may have to remove MCU1 from your car, a difficult process for most people. Some vendors offer a full service – removal and eMMC replacement. In addition, you may be without a drivable car until you get the replacement back. This process only works if the vendor can extract key information from the damaged eMMC and transfer the data to the new part.  It sounds like they have a high success rate, but you should contact the vendor to get a better feel for the success rate.

removed parts

Stack of removed eMMC parts before being destroyed (courtesy of CCI Tesla)

I’ve listed a number of vendors that offer Tesla eMMC data recovery and replacement services. I believe all offer mail-in services from any area. Links are for the vendor’s email or websites. Please contact those you are interested in to find out their full capabilities, pricing, and service areas.

USA Vendors

  • AppleGuru – Boston, Massachusetts area – Also offers mobile MCU removal/installation services
  • Avant Auto Group – Las Vegas, Nevada area; (702) 561-6347
  • Electrified Garage – Florida area; (352) 354-9006
  • Electrified Garage – Massachusetts area; (978) 206-1811
  • EVFixme – Torrance, California area; (949) 682-8261 – Also offers MCU removal/installation services
  • EvFixmeNorCa – San Francisco, California area; (415) 287-9963
  • Gruber Motor Company – Phoenix, AZ area; (602) 863-2655 x500 – Also offers MCU removal/installation services
  • Theo – Maryland area

Outside USA Vendors

  • eMMC Repair – Denmark (serving Norway and Sweden too); +45 9696 1111
  • EV Link – UK; 07904318213 – Also offers MCU removal/installation services
  • Laadkabel Winkel – Netherlands; 040-3041027 – Also offers MCU removal/installation services
  • Santos Collection – Canada, Toronto & Ontario area; +1 416-827-8839
  • TXS – Italy and travel to France/Switzerland; +39.347.4118324 – Also offers MCU removal/installation services

MCU2 Upgrade Option

Another alternative for USA owners is to buy the MCU2 upgrade from Tesla. This uses a flash memory that is 16 times larger, 128 GB.  If everything were identical, that should mean 16 times longevity. Now the MCU2 upgrade offers a lot of additional features, but the older analog AM/FM/XM radio is not compatible with MCU2.  We go into detail in our article on MCU2 Upgrade and AM/FM/XM Radio issues with alternatives and solutions.  Tesla now offers a radio retrofit for $500.

The cost of the MCU2 upgrade including installation is $1500 for pre-HW2.0 cars, and $2000 for HW2.0 cars and later.  For a while, Tesla offered a $250 discount if they used your existing display on newer cars.  It appears they no longer offer this, and all MCU2s now include new displays.  The MCU2 upgrade also replaces the instrument cluster and includes LTE if you have an old car without LTE.  For HW2.x cars, Tesla appears to be also upgrading the AP processor to HW3.0, even if you haven’t purchased FSD yet.

Should I proactively Replace my eMMC?

We recommend that you have Tesla deal with any failures unless you’re interested in the MCU2 upgrade. With the recall, Tesla should deal with it. The downside is it may take months for Tesla to get to your car.  Those that have automatically detected eMMC faults are going to be at the head of the queue.

The failure rate appears somewhat low. Some sound the alarm that every MCU1 will fail. That is true, but it could be 10 more years before your specific unit fails. We really don’t have enough data to state when or if your MCU1 will fail. Some have failed in a little as 4 years.  Vehicle usage does appear to be a factor. 

Wait, there’s more!

Here are some of the links to various other sources, some with differing opinions than ours or were written in the early days before the problem was better understood.

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Cybertruck Top Features

by Moderator

Cybertruck is Tesla’s new spectacular truck! Top announced and expected features include:

Hot Features


All ElectricDelivers economical, quiet, gas-free driving
Stainless BodyThe super-strong stainless steel body requires no paint
Wild stylingThe unique design avoids the hum-drum look of other trucks
Glass CockpitThe instrument panel and control areas appear on a high-resolution screen
Great HandlingLow center of gravity and clever design make for great handling
Smooth RideDynamic air suspension soaks up the bumps in the road
AccelerationHigh-acceleration without lag, 0-60 in under 2.9 seconds with the performance model
Safety8-air bags, traction control, expected 5-star safety rating in every category, blind spot detection, emergency braking, collision avoidance, lowest center of gravity of any truck
Comfortable interiorFlat floor without humps makes for an open airy interior
Supercharging250 kW Fast charging at V3 Superchargers
Automatic BrakesThe parking brake is automatically set when in Park; Automatic braking for collision avoidance
6 AdultsSeating for 6 adults without uncomfortable tunnels in the center positions
Large cargo capacity6.5-foot long, lockable bed
HOA AccessIn select states, such as California, electric vehicles with solo drivers can get access to HOA carpool lanes with an access permit
Traffic-Aware Cruise ControlFollows cars in front at a safe distance and will use braking if needed to come to a complete stop
AutopilotSelf-parking, side collision avoidance, and future Full-self-driving
AWDAll-wheel drive offers increased traction and stability in poor weather conditions
Rear SteeringProvides for tighter turns and improved maneuverability
Latch AttachmentsLATCH child seat attachments in rear seats
StorageStorage areas below the bed, sides of the bed, and front frunk
Bed CoverLockable electric bed cover, auto-stows out of sight, optional
Seat Belt AdjustTwo front seats have height-adjustable seat belt attachments
All LEDsAll lights including headlights and Taillights are all LED
Offroading35″ tires, 15″ ground clearance, with long travel air suspension, top LED lightbar, flat armored underbelly
Load3,500 pounds combined cabin and bed
Bed illuminationBright LEDs along both insides of the bed provide shadowless illumination

Cool Exclusives*


360 VisualizationShows all the vehicles around the car with a 360-degree visualization
Huge Touch ScreenControls and information appear on a huge 15″ high-definition touch screen
Web BrowserA full web browser is built-in and ready to use
Google MapsIncludes 7 years of free updates, with the road, satellite, and traffic views
Full UI AccessWhile driving the passenger and driver have full User-interface access. No annoying lockouts or “lawyer” screens to deal with.
Wireless connectivityBuilt-in 2.4 and 5 GHz WiFi and 3G/4G/LTE cellular connection allows for over-the-air updates and much more
Great RangeWith the Tri-Motor model, it offers 500 miles of EPA range, far more than other non-Tesla production electric cars
Flush Door HandlesAll the doors have flush handles
Auto-LockWalk away from the car and the car locks itself
TailgateTailgate turns into a ramp for easy loading, includes built-in steps
Instant Heat/CoolHeat/Cooling starts immediately when needed (no engine warm-up needed)
USB portsCharge devices, play music files, and record 4-camera dashcam video
Remote Control AppAndroid and iPhone apps allow you to lock/unlock, honk the horn, see where your car currently is on a map, and control charging, get notifications, and more
Extensive LightingLEDs throughout include many conveniences and looks great inside and out
GPS Ride HeightRemembers desired ride height at GPS locations
GPS HomelinkRemembers where you use Homelink and highlights the correct selection
TowingIncludes up to 14,000 lbs towing ability
Ballistic GlassReduces the chances of damage
Dent ResistantVery dent-resistant and bullet-resistant
Tool PowerProvides both 110 and 220 outlets to power tools and more
CompressorBuilt-in air compressor to fill tires, pool toys, balls, and more!
Solar BedThe bed cover can be a solar panel to provide a few miles of additional range  per day (unconfirmed)

* When introduced by Tesla
Some features listed are part of optional packages. Check with Tesla for the latest features and options.

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Dashcam Streaming option

by Dr. Mouse


Expose a dashcam stream.


A dashcam is a great feature, and the simple thumb drive method is brilliant for most users.

However, it does have its drawbacks. Thumb drives get corrupted due to power being cut unexpectedly, the 1h loop is not always enough, you have to take the drive out to access footage, etc.

We’ve seen attempts such as using a Raspberry Pi to get around these issues. While I applaud these attempts, I would suggest an alternative to allow this to be handled in a more elegant manner: expose the dashcam footage as a stream.

My suggestion would be to allow a device to connect as a USB serial port and receive a continuous (MPEG-TS?) stream of footage from the front camera which it can store and/or process as it wishes. Telemetry, like speed/GPS location etc, could possibly be included as a data stream. It could also require a command and/or authentication sequence in order to start the steam.



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There are over 60 processors in the S/X. Other models have fewer processors, but still quite a few.  To get an idea of all the vehicle processors, see our Processors Count article. 

Here we’ll focus on two processor modules that are often confused as to which do what functions. (Sep-2021 Update)

Media Control Unit (MCU)

This refers to the computer module in the center of the S/X dashboard with the touch display prior to January 2021, or the main computer module in every 3/Y and the S/X after January 2021.

The module includes processors, RAM, non-volatile memory, the audio subsystem, audio amplifiers, WiFi, Cellular, Bluetooth, GPS, the Ethernet bridge, multiple CAN bus communications, the LIN bus, USB ports, and more.

The MCU is responsible for the visualizations, all external communications, audio, cellular, navigation, and settings.  It has little to do with Autopilot’s ability to drive other than settings.

There are three versions of the MCU in the S/X:

MCU1 – using an Nvidia quad-core processor was in all S/X cars made from the start of production to February 2018. Tesla now offers a retrofit option to switch from MCU1 to MCU2.  More details are available on the Tesla Infotainment Upgrade page.

Rear of MCU1

There are actually two MCU1 variants, with different connectors. The internals is basically the same in both variants. The red arrow shows the connector change. The older 1004777 is no longer made. For older cars, the newer 1045006 part can be used with an adapter. Some of the earliest 1004777 MCUs only have 3G and do not have LTE. Tesla offers a paid upgrade for those that want LTE, which changes a module within MCU1. All of the 1045006 variants include LTE.

MCU connectors

MCU2 – using an Intel multi-core Atom processor, this MCU began shipping in the S/X in March 2018. MCU2 offers snapper operation, 5 GHz WiFi, a newer Bluetooth version, and additional antennas (external to the MCU2), along with other minor changes.

If you want to confirm which MCU your S/X has, we created an MCU tester. In the browser on the car, enter: TeslaTap.com/mcu

The Model 3/Y architecture is different, with the display and MCU in separate modules. This MCU also uses the same Intel Atom processor and other components used in the pre-June 2021 S/X MCU2.

MCU3 – This is the newest module used in the S/X starting in January 2021 builds. It is likely a liquid-cooled module similar to the 3/Y, but with new processors.

It appears to use the AMD Navi 23 GPU, a major upgrade from prior GPUs.  It handles all three displays, using HDMI for one, and DisplayPort for the other two. The graphics power is considered close to the Sony PS5, which also uses an AMD GPU.  We don’t yet know the CPU used with MCU3, but it is likely more powerful than that used in MCU2.

Early reports have the CPU changed from Intel’s Atom to AMD’s Ryzen chip, which would be a huge performance upgrade.

Autopilot ECU Processor

There are currently four-vehicle hardware variants related to Autopilot.

HW0 –Early Model S with no autopilot capability.

HW1 – First Autopilot, based on the Mobileye chip. It used a single camera, radar, and 12 medium-range ultrasonic sensors. The electronics are co-located with the camera, behind the rearview mirror.

Autopilot HW1 camera and processor assembly

HW2.0 – Tesla’s 2nd generation design, using 8 cameras, 12 long-range ultrasonic sensors, and one front radar. An entirely new ECU processor module was created by Tesla, based on Nvidia’s Drive PX2 system. This ECU is located below the glove box.

HW2.5 – This provides a small update to HW2.0, primarily for redundancy and slightly improved reliability. This version also made possible two non-autopilot features – dashcam and sentry mode with locally saved video.


The early Model 3/Y Autopilot ECU hardware is similar to HW2.5 but uses liquid cooling from the cars coolant loop instead of fans.

HW3 – A major update to the Autopilot ECU using Tesla’s own chip design.

HW3 Neural Net Processor Board

HW4 – A future update to the Autopilot ECU using Tesla’s 2nd generation chip design is now in development. It is expected to have 3x the performance of HW3. It may appear in the 2022 timeframe.

HW Release Sequence and Timeline

Hardware Level Release Date Model S/X Release Date Model 3
MCU1 & HW0 22-Jun-2012 n/a
HW1 17-Sep-2014 n/a
HW2.0 1-Oct-2016 n/a
MCU2 1-March-2018 28-Jul-2017*
HW2.5 1-Aug-2017 28-Jul-2017*
HW3 22-Mar-2019 12-Apr-2019**
MCU3 1-Jun-2021 n/a
HW4 Q3-2022 (Estimate) Q3-2022 (Estimate)
* Start of Model 3 production, but different hardware than S/X with the same CPU as S/X.
** There have been a small number of cars in the summer of 2019 that got HW2.5 AP processor instead of HW3. 2

Hardware Specifications for new cars (no retrofits)

This covers many of the technical components that make up the Autopilot systems over the various hardware versions.

Item HW1 HW2.0 HW2.5 HW3
Front Cameras 1 3 – Narrow 35°, Main 50°, Wide angle 120°
Side Cameras 0 2 - 90°
Side Rearward Cameras 0 2 – 60°
Rear Not used for AP 1 - 150°, RGGB*
Inside (Model 3) n/a n/a 1, RGGB*
Front/Side Camera Filters Monochrome RCCC* RCCB*
Radar Bosch, 525 ft range Continental, 558 ft range
Sonar sensors 12, each with 16 ft range 12 - each with 26 ft range
Core Processors Mobileye EyeQ3 1 – Nvidia Parker SoC** 1 – Nvidia Pascal GPU 1 – Infineon TriCore CPU 2 – Nvidia Parker SoC** 1 – Nvidia Pascal GPU 1 – Infineon TriCore CPU 2 – Tesla chips, each including 12 Exynos 64-bit ARM cores, 2 GPUs, 2 neural network processors and 1 lockstep CPU
RAM 256 MB 6 GB 8 GB 8 GB x 2
Flash Memory 4 GB x 2
Processing Power 1x 40x 40x w/redundancy 420x w/redundancy
Frames per second 36 110 110 2300
Estimated Power 25W 250W (Idle 40W) 300W 220W
Steering Rack Single Power Single Power Redundant Power
* In a camera each pixel is represented by 4 photoreceptors, with a combination of filters: C=Clear, R=Red, G=Green, B=Blue.  Multiple same filters for a pixel increases the light sensitivity. With RCCB, there is no green filter to improve nighttime light sensitivity, and green can be calculated to make a color image for the dashcam.
** Pascal SoC includes 2 Denver and 4 ARM A57 CPU Cores and a Pascal GPU


For older cars that are FSD capable, those owners who purchased unlimited Full-Self-Driving (FSD) get a free upgrade to the HW3 ECU processor.  HW3 upgrades were started for HW2.5 vehicles in the fall of 2019 and HW2.0 vehicles in 2020.

The monthly subscription FSD also requires the car have the HW3 ECU processor.  If the car does not have the HW3 ECU and it is capable of getting the retrofit, there is a $1000 charge to get the HW3 ECU.

For owners of HW2.0 cars, the addition of HW3 ECU provides the hardware necessary for FSD. It also enables the dashcam and Sentry mode features, although the quality is not great with MCU1.  Owners can also upgrade the MCU1 to MCU2.

Autopilot and Safety Related Features

The Tesla Autopilot terminology has changed over the years. The first Autopilot system, using one camera, is now informally referred to as AP1.  Starting with the new hardware HW2.0, Tesla changed the feature name to Enhanced Autopilot (EAP) with several extra features. In March-2019, Tesla dropped EAP and created a lower cost, less featured Autopilot simply called AP. In April, this became standard on all new cars ordered from the web (It’s not standard on the special order Model 3 SR).  This new AP is a subset of EAP features, with other EAP features being moved into the FSD (Full-Self-Driving) feature set.


Those owners that purchased EAP will continue to get all of the EAP features and get upgrades in the future. Smart summon for example is an FSD feature, but EAP owners also got this feature.

FSD features are optional and can be purchased with a new car, or purchased and activated later.  Instead of buying FSD, Tesla plans to also offer a monthly subscription option. Details and the price for the subscription service has not yet been set.

The following feature chart only applies to vehicles made on 17-Aug-2014 and later. Earlier cars do not have any of these features.

Feature No AP AP1 AP* EAP* FSD*
Front Collision Avoidance Yes Yes Yes Yes Yes
Lane Departure Warning Yes Yes Yes Yes Yes
Lane Departure Avoidance Yes* No Yes Yes Yes
Emergency Lane Departure Avoidance Yes* No Yes Yes Yes
Side Collision Avoidance Yes* No*** Yes Yes Yes
TACC No Yes Yes Yes Yes
Autosteer, accelerate and brake No Yes Yes Yes Yes
Autopark No Yes No Yes Yes
Auto Lane Change No Yes** No Yes Yes
Read Speed Signs No Yes Yes Yes Yes
Summon No Yes No Yes Yes
Smart Summon No No No Yes Yes
Navigate on Autopilot No No No Yes Yes
Respond to Traffic lights and stop signs No No No No Yes
Full Self Driving No No No No Future
* Requires HW2.0 or later or all Model 3/Y vehicles
** AP1 requires confirmation when traffic safe
*** Was available prior to v8.0 software, but not was not effective and was removed

Autonomous Driving

The following chart shows the levels of autonomous driving as defined by the Society of Automotive Engineers (SAE).

SAE Level Description Monitored By
0 No automation Driver
1 Assisted driving, typically with cruise control Driver
2 Advanced assisted driving with steering, braking, and steering in select environments Driver
3 Conditional automated driving, but the driver may be asked to take over System
4 Highly automated driving, driver not required to take over System
5 Fully automated driving can handle anything a human can. System

Currently, Tesla offers a level 2 type of autonomous automation option. Tesla’s goal is to transition to level 3 and eventually to level 5, which is called FSD. Tesla announced in early 2020 that a portion of  FSD should be available by the end of 2020 depending on regulations. Complete FSD will depend on completed software development and regulatory approvals in each jurisdiction. 

Keep in mind there are conditions where FSD will not work, conditions where humans should not drive either, although some humans foolishly try. Some of these conditions include:

  • Heavy fog
  • Heavy snow/whiteout
  • Deep snow on roads
  • Hail
  • Floods
  • Monsoons
  • High Winds (Hurricanes & Tornadoes)
  • Fires sweeping over a road
  • Lava flows
  • Mudslides

For 99.99% of daily driving, FSD should work fine – just like humans. We suspect at some point FSD may even be tied into the weather network to determine if there will be an impediment to reaching the destination and advise of the issue.

Part Numbers

Item Model Part Number
MCU1 with display, early cars, no longer available S/X 1004777-00-A
MCU1 with updated display and LTE, the latest version S/X 1045006-00-J
MCU1 Internal Tegra board with 64 GB eMMC S/X 2728212-S0-B
MCU2 with display S/X 1451809-S0-B
MCU3 and Autopilot ECU S/X 1637790-S0-D
Autopilot ECU 2.0 S/X 1078321-00-C (MS)
Autopilot ECU 2.5 S/X 1125800-70-C
Autopilot ECU 3.0 S/X 1655000-00-F*
MCU2 and Autopilot ECU ** 3/Y 1098058-S0-L
* The 00 variant has HDMI port, perhaps for development
** The MCU and Autopilot ECU are two boards in the same module and are functionally similar to the S/X MCU2's computer and Autopilot ECU
part structure
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Our latest analysis of the various Model 3 audio systems. We’ll continue to update this analysis should Tesla make further changes and we learn more! (Jun-2019)

System Features
Feature SR
Partial Premium
Internet Streaming No No Yes
USB Ports for music No No 2
Total USB Ports 4 4 4
Total Amp Channels 7 7 14
Tweeters* 0 1 3
Midrange* 4 4 9
Woofers* 2 2 2
Subwoofer No No Yes, 8″, dual coil
Total Amplifier Power** 200W 200 W 560 W
Immersive Sound No Yes Yes

*  SR and SR+ are our early WAG
** Not stated by Tesla, our WAG of peak power, typical of vehicle audio specifications.


Speaker Components


Type Part Number Size Impedance Watts
Sub-Woofer 1109561-00-A 8” (200 mm) 2×40 ohm 160 W
Woofer 1079744-00-E 8” (200mm) 4 ohm 80 W
Full-range 1079742-00-A 4” (100 mm) 3 ohm 33 W
HD effects 1088459-00-B 2.5” (60 mm) 4 ohm 2 W
Tweeter, Active 1079741-00-A 1” (25 mm) 4 ohm 25 W
Tweeter, Passive 1098737-00-B 1” (25 mm) 4 ohm 25 W


Speaker Locations*
Location SR
Partial Premium*
Front Dash 2 – 4” mid-ranges 1 – 1” tweeter
2 – 4” mid-ranges
1 – 1” tweeter
3 – 4” mid-ranges
Side Mirrors No No 2 – 1″ tweeters
A-pillar No No 2 – 2.5” mid-range
Front Doors 2 – 8” woofers 2 – 8” woofers 2 – 8” woofer
Rear Doors  2 – 4″ mid-ranges  2 – 4″ mid-ranges 2 – 4” mid-ranges
Rear No No 2 – 4″ mid-ranges
1 – 8” Subwoofer

*  SR and SR+ believed to be accurate – info from other owners

M3 Speakers

Amplifier and 15 Speaker Placement for Model 3 – Premium


Inside Tesla’s Audio System

We’re still digging into the details, but here are a few things we’ve found out so far. The premium amplifier is mounted next to the subwoofer in the rear of the car. This amplifier powers the dual-coil subwoofer, the two rear trunk speakers and four-door speakers. It’s likely the dash speaker amplifiers are split between vehicle controller left and vehicle controller right modules. In the front center, the tweeter is a passive design connected via a crossover to the center mid-range.

In the S and X, almost every speaker gets a separate dedicated amplifier channel. Assuming the 3 is designed the same way, this means there are 14 amplifiers. Having discrete amplifiers for each speaker allows for far better acoustic tuning during the design by Tesla’s audio engineers. Typical stereos in most other vehicles use four amplifiers.

The speakers are made for Tesla in China. Most of the audio equipment appears to be created by and made for Tesla and is not some rebranded products. Tesla logo appears not only on labels, but molded into plastic parts such as the polycarbonate speaker baskets.

The tuner is manufactured by Harmon, made in Mexico. This is exclusively FM, and there is no hidden AM radio in the module and only one antenna connection that connects to an FM radio RF amplifier. For comparison, the original S/X tuner module was made by Panasonic and included both FM and AM tuners.


Audio Controls

Use the tone and balance controls to adjust the system to your personal preferences. For example, if you have some hearing loss in the upper frequencies you might increase the treble. If you listen to books or talk shows, you might increase the mid-range to improve vocal clarity. Be aware that other passengers may not have the same hearing desires as you so sometimes a compromise will be necessary.

While you could jack all the tone controls up to increase the volume, unless you really need that extra volume, it will add distortion between the bands. It’s is best to have a least one band set to zero and adjust the others to get the overall effect you want. The further a band is set zero, the equalizer will add some phase distortion. While many cannot hear phase distortion, using values with +/- 2.5 dB is ideal.


Audio Control Screen


Depending on if you have any passengers, you may want to adjust the balance to the center or favor the front or rear soundstage. Non-premium systems have weaker rear speakers, so you may shift the fader further back than those that have the full premium system.

The full premium also offers an immersive sound option that provides a multi-channel synthesis from the stereo source material. It’s in the Options menu of Audio Settings. It’s worth trying out. The two small speakers above the A-pillar are only active when immersive sound is active.


More From TeslaTap on Audio


DIY Upgrade Products
  • Front dash left/right 4″ speaker upgrades: Infinity REF-4022
  • Sound deadening material: Noico Dynamat


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12 Volt Battery Compendium

by Moderator

Some owners may be surprised to learn their car includes a 12v lead-acid battery. We’ll explain why and delve into everything about the 12v battery used in Tesla vehicles today.  (Updated Jun-2020)

History and Use

The earliest Tesla roadsters didn’t include a 12v battery but used a portion of the main lithium-ion pack to supply 12v for accessories and lights.  This was not ideal, and in 2010 Tesla switched to a separate 12V battery in the Roadster 2.0. All Tesla vehicles since that time also include a separate 12v battery.

Roadster battery

2010 Roadster 2.0 12v battery position

The reason for a separate 12v battery is to power critical systems in the event of a high-voltage battery disconnect. This keeps key systems operational such as emergency blinkers, airbags, seatbelt pre-tensioners, brake booster, and a host of other systems. The high-voltage battery might be disconnected due to several rare events – such as a high-impact crash, internal main battery pack problems such as some types of cell failures, a contactor failure, and a few other unlikely situations.

Many parts of the Tesla vehicles today are powered by the 12v battery, including:

  • All lights, such as headlights, turn lights, fog lights, taillights, backup lights, license plate, and interior lights
  • LCD Display –Instrument Cluster (S/X) and the main display
  • The MCU and many modules with processors (50+ in the Model S/X)
  • Non-traction motors, such as windows, liftgate (S/X), wipers, washer fluid, seat motors, side mirror adjusts, sunroof (if equipped) charge port door, steering assist, fans, valves, and coolant pumps
  • An audio system including tuners, antenna amplifiers, and audio amplifiers
  • Safety systems, such as airbags, brake booster, and seatbelt pre-tensioners
  • Autopilot systems including cameras, sensors, and radar
  • Heated items, if equipped such as seats, steering wheel, washer nozzle, side mirrors, rear defrost and camera heaters.
  • Other items like the alarm, rearview mirror dimmer, USB ports, horn, HomeLink, air suspension (if equipped) and various latches (doors, trunk, frunk, glovebox)
  • High-voltage battery pack contactors

Only a few items are directly powered by the high-voltage battery pack. This includes the traction motor(s), the a/c compressor, cabin air heater, battery coolant heater (S/X only) and the DC to DC converter for 12v power and charging the 12v battery.

Tesla ran into a major snag with the introduction of the Model S in 2012.  The 12v battery was sourced from an American firm, who unbeknownst to Tesla, outsourced the battery to China, and the Chinese company outsourced it to Vietnam! The quality was sub-standard and rarely lasted more than a year. Tesla switched vendors in 2013 and replaced all the marginal batteries in early build cars with a far more reliable battery under warranty.


Battery Types

The Model S uses a 33 or 35 Ah sealed AGM (Absorbed Glass Mat) deep-cycle lead-acid battery. One early supplier for the pre-refresh Model S was the C&D Technologies DCS-33IT, now discontinued.  For these older cars, Tesla now recommends the C&D DCS33-UNCR.  For the refreshed Model S, Tesla now uses the AtlasBX U1 a 35 Ah AGM battery.

C & D Battery

Model S C&D Technologies Battery

The Model X uses a 40 Ah AGM battery. The primary battery used is the AtlasBX with the model 60B19RS.

The Model 3 uses a 45 Ah, AGM Battery. One supplier is AtlasBX with the model 85B24LS.

Model 3 Atlasbx battery

Model 3 AtlasBX battery

AGM batteries provide more power for size and weight than traditional lead-acid batteries. Deep cycle versions, like those used in Tesla vehicles, are designed to be repetitively charged and discharged. If you were to use a typical lead-acid battery in this application, it may only last a few months!  AGM batteries are also sealed, which eliminates acid spilling accidents and the need to periodically add water.

Battery Longevity

In new Tesla cars, the 12V battery lasts about 3-4 years for most owners, although paradoxically, if you put a few miles on the car, it may last as little as 1-2 years. The difference is how many discharge/charge cycles the battery goes through and how deeply the battery is discharged. When driving, the DC-DC converter helps power the 12v system, and fewer charge cycles occur. A car left sitting, will need more charge cycles, and will age the 12v battery faster.  Some Model S owners still have the original battery after 4 years and over 170,000 miles of use!  The Model 3 is too new to evaluate its battery longevity, but Tesla made considerable changes to the electronics, which may increase battery life as well.

AGM life cycle

AGM life cycle – deeper discharges will result in fewer cycles

Your Tesla maintains power for some key computer systems all the time, so you can disarm the alarm, unlock the car with your FOB (or phone for the Model 3), and when you enter the car, everything starts up without any pause. In addition, the cellular connection for remote access needs power. All these systems require power even when the car is not in use. This is often called the car’s vampire drain. Tesla, via software, has significantly reduced the vampire drain of all cars over the years, but it can’t be eliminated.

Newer cars also use modules that take a bit less power when the car is parked, so that helps. Even the oldest cars should easily get 2-3 years of 12v battery life, although there can be rare exceptions. Just like ICE cars, sometimes the battery fails prematurely.

What is Different About How Tesla Uses the Battery?

Often an ICE car goes 3 to 5 years before replacement.  The way the 12v battery is used in ICE cars is quite different than an EV. When the motor is running, normally the alternator powers all the 12v items in the car and charges the battery. The primary use of the 12v ICE battery is to start the car, which takes 2-3 seconds with very high currents.  After starting the car, the battery is not really used. When the car is off, very little power is used, otherwise the battery would die in short order.

A few BMW ICE models, and perhaps other makers, use a far larger battery and intermittently use the alternator. This reduces gas use with less alternator drag on the motor. The downside is the far more charge/discharge cycles means the battery is replaced about once a year, a $700 hit in the BMW!

Improving Longevity

Tesla provides one option that may slightly improve the 12v battery longevity if that is important to you. Turn off Mobile Access. This means you cannot access the car via your phone app.

Mobile access on the Model 3

Mobile access on the Model 3, and is similar on the S/X (v9+)

For most owners, the battery replacement cost is a negligible part of the ownership costs. Having remote access is a great feature, usually worth trading off for a slightly shorter 12v battery life.

Charging the 12v Battery

The 12v battery is always charged via a DC-DC converter from the main battery pack. This takes the packs high voltage and converts it to about 14v to charge the 12v battery. It’s a bit more complex, as the voltage to charge the AGM battery is tightly regulated and is compensated due to temperature.


Even when you are charging the car, only the main pack is connected to external power.  While quite rare, if the DC-DC converter fails, the 12v battery can no longer be charged.

The Gen 2 DC-DC converter in the refreshed Model S accepts 220 to 430 VDC at 15 amps and outputs 9 to 16 VDC. When outputting 12 VDC, it can deliver about 200 amps.

DC-DC inverter (Model S, Gen 2)

DC-DC converter (Model S, Gen 2)

The Model 3 and Y integrates the charger and the DC-DC converter into a single package, the PCS (Power Conversion System).

Battery Failure Warning

Tesla included additional hardware at the battery to help detect when the battery is nearing its end of life. Should the battery get within 3-4 weeks of the end, Tesla warns you with a clear message that the 12v battery needs replacement. This is dramatically better than most ICE cars, where the battery dies without much if any, warning.

Warning message

Warning message for the Model S/X (left) and for the Model 3/Y (right)

Part of the reason ICE car batteries often die unexpectedly is the type of battery used. A standard lead-acid battery will degrade over time, but the lead sheds during use and can short out plates at some point, causing the immediate cell death. An AGM battery, like the ones Tesla uses, should never fail this way.

Battery Location

In all Tesla, the 12v battery is located under the hood. Over the years and models, it has moved around somewhat. The classic Model S RWD had the battery deep on the passenger side in front of the firewall. This location is tricky to get access too, but a trained Tesla tech can often replace this battery in less than 20 minutes. For someone not familiar with the process, it will take quite a bit longer.

Starting with the AWD Model S, the battery was relocated to be easier to access and replace – on par with most ICE cars. The location remains about the same for the S, X, 3, and Y. There are several easy to remove plastic panels to gain access to the battery. No tools are required to gain access.

Battery Location

Refreshed Model S Battery Location (with cabin air inlet panel removed)

What Kills an AGM Battery?
Over time the ability to charge and discharge effectively slows due to sulfation. Lead sulfate accumulates on the negative and positive parts within the battery during discharge. Over many charge/discharge cycles this process reduces the amount of energy that can be stored and extracted.  At some point, the battery is considered bad, even though it continues to work at some level. With proper instrumentation, such as done in the Tesla, a degraded battery can be detected well before the useful end of life.

Fully discharging an AGM battery is bad, but not normally fatal. Fully discharging an AGM battery does reduce the batteries’ longevity. Normally this never occurs in a Tesla, but if a vehicle is not connected to a charger, and the main battery is drained to 0% SOC (which has a hidden remaining charge), the 12v battery will stop being charged to protect the main battery. Within a few days, the 12v battery will be drained.

Dead battery

One rare failure mode is open contact between two cells.  This is usually caused by improper manufacture of the battery or an external short.  The battery voltage goes from normal to zero as soon as the open occurs, usually early in the life of the battery.

Heat is also bad for an AGM battery, but the heat conditions encountered in a Tesla are fine. AGM batteries are not suitable in an ICE engine compartment that exceed the AGM’s maximum charging temperature of 140°F (60°C).

Why Lithium-Ion 12v Battery is a Bad Idea

There are 12v lithium-ion drop-in replacements for ICE car batteries. These are quite a bit more expensive but do weigh less – so you’d think they would be great in an EV. Not so fast. Turns out for Tesla’s application the frequent deep charge/discharge cycles would greatly shorten the life of a lithium-ion battery designed for ICE cars, perhaps only lasting 6 months to a year. Since there is no climate control on the 12v battery, it’s life would also be shortened if you encounter climate extremes. Lithium-ion 12v battery makes little economic sense in a Tesla.

Why Lithium-Iron Phosphate 12v Battery is a Good Idea

Ohmmu makes a 12v battery replacement specifically for Teslas. These batteries use different chemistry that works in a Tesla and should give superior life over the standard AGM battery. This special chemistry is not as energy-dense as conventional Lithium-Ion cells, so they are not effective for the main battery, but can work well in Tesla’s 12v application. These batteries handle a wide temperature range, support deep discharges, and many more charging cycles than the AGM battery. Ohmmu includes a 4-year warranty. The only downside we see is the expense.

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