Howdy everybody! This is a great forum with tons of helpful info. I posted this issue in another thread but figured I'd start my own for a little more exposure.

My wife's '04 has had the BAS/ESP light on for a while now. We're fixng on selling the car, so it's in the shop and they're trying to troubleshoot the source of the light, but apparently the car is not throwing any codes whatsoever. Sounds like they've tried both OBD as well as the Mercedes diagnostic tool.

Anybody know what could cause this? Also, the brake pedal has been mushy for a while, can't help but to wonder if that's associated with the BAS/ESP? I've tried all the simple fixes: new battery, steering column switch reset, brake light switch must work because the brake lights work. Could a burnt out turn signal cause this??

Someone mentioned earler that the mushy brake could be the culprit, does anyone else have any experience with this happening?

Thanks!

 

Have you tried this:

Synchronizing ESP


If the power supply was interrupted (battery disconnected
or discharged), the BAS/ESP malfunction indicator
light may be illuminated with the engine running. To
re-synchronize the ESP, and cancel the malfunction indicator
light, the steering angle sensor will need to be
recalibrated.
1. Turn the ignition switch to the ON/RUN position.
2. Rotate the steering wheel to the center position.
3. Rotate the steering wheel completely to the left, and
then rotate the steering wheel completely to the right.
4. Bring the steering wheel back to the center position.
5. The BAS/ESP malfunction indicator light will go out.
If the BAS/ESP malfunction indicator light is still illuminated,
the vehicle should be serviced at an authorized
dealer.

 

This will usually work but I do this procedure with the car running and if the light does not go off immediately I drive a mile or two and the BAS ESP light will reset and turn off

 

Could be a wheel speed sensor.

 

Hi Bill, I gave that a try with the engine off and key in run, and then also with the engine running. No luck either way. Thanks though, I appreciate the suggestion.

 

Intersting theory, I'll have the shop look into that. Thank you!