ASR/ABS lights on 140 - PeachParts Mercedes-Benz Forum

Toxicant · #1 09-03-2003, 03:32 PM

Hello all,

I've been searching for awhile and can't seem to find the answers to my questions.

asr/abs lights came on the other day while driving, I stopped and checked the asr fluid and it was low. I topped it off and still the lights come on. When you start the car the bulb check works and then the lights go out. As soon as you start to drive and hit the brake pedal for the first time they both come back on.

Is there a way to re-set the computer or the lights being on are showing a hard fault. Second, is there a way to pull codes out of a 92 140 without a tester?

Thanks guys!

Ron

stevebfl · #2 09-03-2003, 04:29 PM

ASR and ABS

Pin #6 on the 38 pin connector can be diagnosed by the impulse method (see the DIY article on evaluating engine controls for a basic description of the method.

pentoman · #3 09-03-2003, 04:55 PM

Steve - On diagnosis only for a customer yesterday I saw a similar problem on a 2000 W210 E320T, we pulled the codes and had something like

xxxx-brake light switch
xxxx-Brake light switch (plausability vs. brake assist)

I presume this is to do with the brake assist function. Is there a simple switch on the brakes for that, or do they use something to guage how hard you hit the brakes, and/or how quickly you come off the pedal, and was that the problem being suggested by the machine?

just curious

Russ

stevebfl · #4 09-03-2003, 05:25 PM

It looks like the brakes switch S9/1 would be the problem. That is the switch on the pedal.

The BAS has a BAS release switch A7/7s1 that detremines when the plunger is unloaded in the brake booster (brakes off) and a diapram travel sensor A7/7b1 that determines how fast the brakes are applied.

The first code looks to implicate the S9/1 and the second is saying that the BAS switches conflict with the S9/1 input. It could be the BAS value that is wrong but since there is a separate code for the switch in particular and because its cheap and a common failure, I would go there. BTW the S9/1 is an input to the ESP module and comparisons are made in one controller or the other via the CAN.