2015 Chevy Express 2500 4.8 Speed Limiter

[bgibson7]

Hello,

I am working on subject vehicle that a customer purchased and it currently is governed at 77mph. I pulled the tune and found that speed limiter by fuel was 77mph. I changed that to 98 and source to calibration. I then flashed the PMC and TCM calibration and the vehicle is still limited to 77mph. I have dug though all of the engine and transmission tabs in an attempt to find another limiter but I am not able to. I then changed the enable RMP to 7,000 in an attempt to disable the speed limiter altogether but again the vehicle is still limited to 77mph.

I am attaching the tune file I pulled from the vehicle as found. I am also attaching the tune file with the above mentioned changes.

Any help in pointing me in the right direction is greatly appreciated.

Thanks,
Blake

[Alvin]

Try this

2015 Express 2500 as found. try this.hpt

[bgibson7]

Try this

2015 Express 2500 as found. try this.hpt

Alvin - Tried your tune file and unfortunately the vehicle is still limited to 77mph. When the vehicle reaches about 75mph it will up-shift and drive as if you lifted your foot off the throttle or set the cruse control to 77mph.