Hi everyone,

I’m reaching out to see if anyone has experience with substituting an EPS firmware file from a different model that uses the same EPS motor/module. Specifically, I’m curious whether I can use the EPS firmware files from a 2018 Buick Regal in my 2023 Cadillac XT4, given that both vehicles share the same motor/module, as long as I retain my correct VIN.

 

The reason for this inquiry is that the 2018 Buick Regal allows Lane Keep Assist to be enabled at lower speeds (6 mph), whereas the Cadillac XT4 only engages above 30 mph.

 

Alternatively, if it’s possible to modify the firmware file to lower the minimum steering speed and perhaps increase the steering torque, I’d be interested in exploring that option as well. This modification is beyond my current expertise, but I’m willing to offer a substantial bounty if someone with the necessary skills can assist.

 

Thanks in advance for any insights or assistance you can provide.

 

 

 

 

 

In all likelihood, you won't be able to simply package a cal file from a different vehicle with other cal files in an archive.  (At least with the BCM it will result in a soft-brick of your car.)

 

You'll need to be able to figure out which byte or byte sequence controls the minimum steering speed and change that within the cal file for your XT4.

The BCM seems more complex since it serves as the relay for all the car's features. I've flashed the BCM within the same model year to enable heated seats, steering wheel, etc., but flashing it with firmware from a different model could definitely cause issues.

 

I believe the EPS is simpler, but it might encounter problems if it doesn't communicate correctly with other modules. The EPS has three files . Operating system, system, and calibration. (using the same utility file). I may try swapping the system files to see if it takes. I should be able to flash back to stock if it doesn't or it may not even flash at all.   

 

Next, I was considering decoding the firmware, but it seems that I’d first need to decode the hex code by identifying the EPS processor. After that, I would need to analyze the raw logic provided by the decoder to hopefully locate the line that controls the steering speed. I know this has been done for Hondas, so it’s possible, but likely by individuals with more experience in the auto industry.

 

  

 

 

On 8/17/2024 at 12:44 AM, Pinballben F said:

The BCM seems more complex since it serves as the relay for all the car's features. I've flashed the BCM within the same model year to enable heated seats, steering wheel, etc., but flashing it with firmware from a different model could definitely cause issues.

 

I believe the EPS is simpler, but it might encounter problems if it doesn't communicate correctly with other modules. The EPS has three files . Operating system, system, and calibration. (using the same utility file). I may try swapping the system files to see if it takes. I should be able to flash back to stock if it doesn't or it may not even flash at all.   

 

Next, I was considering decoding the firmware, but it seems that I’d first need to decode the hex code by identifying the EPS processor. After that, I would need to analyze the raw logic provided by the decoder to hopefully locate the line that controls the steering speed. I know this has been done for Hondas, so it’s possible, but likely by individuals with more experience in the auto industry.

 

  

 

The easiest way if you want lane keep assist is to calibrate all modules related to features to add on XT4, 
find XT$ same as your car model year with RPO UHX UGN UEU UEC and add all modules and wirings needed,, not just calibrations, you need to add hardwares.

 

Thanks for the info. I have already enable the lane keep assist feature, but I am looking at modifying the ability of the feature. I really want to flash a 2018 Buick Regal EPS firmware as its the same part number. This would allow a better min speed steer (6mph vs 30mph). I am not sure how the rest of they system will handle it if at all. I feel like it should work, but it could also brick the EPS which would be difficult to replace. If anyone has experience with using different model EPS firmware or have more information on modifying the firmware let me know.