Updated: Mar 20
A "Bricked ECU" is an Engine Control Unit that has been rendered inoperable, and now only can function as a brick or paperweight.
While bricking an ECU is uncommon, it is always a risk when tuning a vehicle. A bricked ECU is usually the result of a communications issue that happens during programming. This can be due to several reasons:
Other components of the vehicle interrupting the ECU
Noise on the wires running to the OBD port
Damaged ECU Hardware
If an interruptions occurs during programming, then your ECU *May* be left inoperable. With current commercial software, there are safeguards and recovery options that protect your ECU during most failures, however, there is always an inherent risk of failure.
The processor in your ECU contains "Program" data as well as "Calibration" data. The program data is the portion of the ECU's memory that contains instructions on how to run the vehicle, as well as instructions on how to transmit data over the OBD2 port. The calibration data tells the ECU about your specific vehicle (displacement, injector size, desired fueling, desired timing, etc...) so that it can make the correct calculations needed in order to perform its functions.
If the program data portion of your ECU's processor is corrupted (interrupted) when it is being programmed, the ECU may no longer be able to communicate. If it can't communicate, it can no longer be programmed, and it is then a brick. Many ECUs require the entire processor (program data and calibration data) to be reprogrammed every time the ECU is updated. In this situation, program data will be re-written to the ECU, even though it has not changed. If there is a communications issue during the transfer of the ECU's program data, then the ECU may no longer be able to communicate.
Can a bad tune brick an ECU?
EFI Tuners do not need to modify the program data of your ECU to do their job. Often they do not have access to modify the Program data of your ECU to begin with. Reputable tuning software does not expose the program data portion of the ECU for modification. This is a safeguard to prevent the ECU from becoming inoperable. In order to tune your vehicle, your tuner opens their tuning software, adjusts the appropriate data, and then clicks the "Write To Vehicle" button. Nothing that your tuner is able to enter into the ECU will cause it to be inoperable, as changes are only made to calibration data and not program data.
No matter what data your tuner loads into the calibration portion of your ECU with reputable tuning software, the program data remains the same. With correct OEM program data, you can communicate with the ECU, and reload a working calibration onto it.
While a bad tune can't brick an ECU, electrical issues and neglect can. A dying battery in the car or the tuner's laptop can cause communication to stop. Simply unplugging the USB cable while programming an ECU can cause a failure as well. Precautions can and should be taken to ensure a successful write.
Here are some of the precautions we take:
Verify battery voltage during pre-tune check.
Verify charging system functionality during pre-tune check if possible.
Verify the vehicle can be logged over the OBD2 port.
Keep the doors closed during the write process.
Keep the radio and AC off during the write process.
Swap laptops if the battery falls below 30%.
Run the OBD2 programming cable over the steering wheel to keep it away from feet.
With every responsible precaution taken, inherent issues can still lead to a bricked ECU. Older vehicles with aging electrical systems get more failure prone by the day. Newer vehicles with many complicated interconnected controllers add risk to the programming process. Security and Anti-theft systems occasionally power down vehicles as they are being programmed.
Coverage Without any way of knowing what underlying electrical issues your car / ECU may have, your tuner cannot reasonably take responsibility for a bricked ECU. Your tuner didn't build the vehicle, nor did they make the equipment being used to program your vehicle's ECU. Your tuner wants to get paid to successfully tune your vehicle, and will likely have taken every possible precaution to ensure success.
Neither you nor your tuner will know there is an issue until they attempt to write to your ECU, rendering it inoperable. New ECUs are often hard to source. Returning your vehicle to a tune-able state can be an expensive time consuming endeavor to undertake. For many, the vehicle being tuned is a daily driver, and a bricked ECU can leave them without a way to get to work.
We can't accept liability for your vehicle's bricked ECU. We take our precautions, and attempt to perform the service you asked us to perform. We're here to help however we can, but there is unfortunately nothing more we can do to avoid a bricked ECU. What we've found out that we *CAN* do to help, is crowd-funding support for this situation.
To help protect your investment, we offer a chance to opt-in to "Brick Coverage" for an additional $100, due when scheduling an appointment with us. Should you opt-in to our Brick Coverage, we will replace one ECU that becomes inoperable during our services with a working replacement up to $750. Should we replace your ECU under this coverage, it is then your responsibility to diagnose and resolve the communications issue preventing us from calibrating your vehicle. If you'd like us to help with this we can, however, dealership level service may be needed to troubleshoot the other control modules that may be interfering with the ECU. Brick Coverage is not offered for vehicles that have previously used Brick Coverage. We are not offering Brick Coverage if you request that we tune your vehicle using tuning software that is not our recommended product for your vehicle. Fords, for example, can be tuned with both SCT as well as HP Tuners (which is cheaper). SCT has better error handling than HP Tuners, and is our preferred tuning software for these vehicles. Should you decide to have us tune your Ford with HP Tuners rather than SCT, we will not be offering Brick Coverage.
In the unlikely event that your ECU is bricked, you have not purchased Brick Coverage, and you are not having us correct this condition, we'll need you to tow your vehicle off of our property within the next 48 hours. We schedule our workloads so that we can keep our customer cars inside, and value our shop space.
At the end of the day, I can't tell you whether or not to opt into this coverage, but I can help by being transparent. Below are all of the ECUs we have ever bricked in our many years of tuning:
2008 Ford Mustang GT500