Esp and Bas Light are on

howard49 · Apr 11, 2014

I have a 2008 dodge ram 1500 4.7, my esp and bas warning lights are on i have tried replacing wheel sensors(i have replaced front and rear didn't work). I heard that air in the brakes could cause the light bleed all of the calipers and put fresh brake fluid in still the light is on. I have scanned the truck numerous times and i come up with a C121E code brake pressure sensor comparative. I'm running out of ideas and would like to get this problem solved. Thanks

RonJon '06 · Apr 11, 2014

Have you replaced the brake pressure/light switch located behind the brake pedal? Its a $10-15 part and could cause that code. If your brakes are working normally and you're just getting the warning lights then that could be the problem.

howard49 · Apr 12, 2014

I will try that abs still works so hopefully this will be the problem I'm hoping it's not the abs module. Thanks for the help

howard49 · Apr 13, 2014

I replaced the brake light switch still the lights are on!! Im not sure what else to do to fix this problem.

RonJon '06 · Apr 13, 2014

Here is a list of probable causes I found online:

1) Incorrect brake pedal adjustment
2) Master cylinder malfunction
3) Brake booster malfunction
4) Incorrect installation position of stop lamp switch
5) Malfunction of stop lamp switch
6) Brake drag
7) ASC-ECU malfunction

Although it seems like a long shot brake drag could be caused by a stuck brake caliper. Maybe check the vacuum line to the brake booster.

Esp and Bas Light are on

howard49

Junior Member

RonJon '06

Senior Member

howard49

Junior Member

howard49

Junior Member

RonJon '06

Senior Member

Similar threads

Latest posts

Members online

Forum statistics

Share this page