ABS and ASR lights come on after hard acceleration

[mike52787]

So today I was driving my e500, rather spiritedly. Came up on a highway on ramp that was clear and did what we all do. Once I put my foot down I noticed my ABS and ASR warning lights had come on. so I pulled over, shut the car off, did a little visual inspection under the front and rear end and found nothing. when I restarted the car the lights were gone. Issue solved! Until I did it again. Same issue. Any ideas?

 

[gsxr]

Sounds like limp mode... resets when you re-start the car. Check codes, clear codes, check and see what codes recur if it happens again... search the forum for more details, it's been discussed quite a bit.

 

[mike52787]

Sounds like limp mode... resets when you re-start the car. Check codes, clear codes, check and see what codes recur if it happens again... search the forum for more details, it's been discussed quite a bit.

Hmm, never got a CEL and it didn't feel like it was down on power at all. The throttle works properly. I'm thinking maybe it's a front speed sensor? I did just have the front end apart and replaced my LCAs.

 

[gsxr]

Sorry, I should have clarified... the CEL only illuminates for emissions-related items. Throttle control is not considered emissions, so you won't get a CEL with limp mode. The other codes must be checked with a digital scanner or hand-held blinker box.

If throttle control was 100% normal with ABS+ASR lights on, there was some other fault (not limp mode) causing the lights. However, it sounded like you didn't drive long enough after seeing the lights on to notice if throttle control was abnormal?

 

[mike52787]

Sorry, I should have clarified... the CEL only illuminates for emissions-related items. Throttle control is not considered emissions, so you won't get a CEL with limp mode. The other codes must be checked with a digital scanner or hand-held blinker box.

If throttle control was 100% normal with ABS+ASR lights on, there was some other fault (not limp mode) causing the lights. However, it sounded like you didn't drive long enough after seeing the lights on to notice if throttle control was abnormal?

After the ABS and ASR lights came on the second time I just kept driving. Was on my way home and probably did about 50 trouble free miles with the lights on. I ordered all the parts to make my own blink code reader, so hopefully I will have some hard info soon. I assume the codes stick even after the lights are off on the dash?

 

[gsxr]

OK... that doesn't sound like limp mode, but instead a different problem, which is probably good. Driving in limp mode isn't fun.

Yes, the codes will remain until cleared, but if you've never checked/cleared codes before, you'll get "code diarrhea" with a bunch of red herrings that could be a decade old. Which is why you want to clear everything, then see what codes (if any) recur quickly, or after the lights come on next time.

 

[mike52787]

Found my issue! read codes and it came out to the left front wheel speed sensor. I checked and noticed the wiring was chafed from coming in contact with the wheel or brake rotor. I must not have clipped it back in correctly when reassembing the front suspension. I'm happy it was something easy.

 

[mike52787]

Great. so today is the day I learn that the late style abs sensors are NLA. Part number A1245403117. well, if anyone has a spare please let me know. I have one of the old style ones off of my parts car, but that doesn't do much for me.

 

[gsxr]

Doh!

Good news is that all facelift 124's in USA use the same sensors, so any 94-95 E-class is an appropriate donor.

Can you repair the wires, instead of replacing the whole sensor?

 

[mike52787]

Well, I'll give it a shot. now I know more parts to hoard from the junkyard

 

[gsxr]

Well, I'll give it a shot. now I know more parts to hoard from the junkyard

I know, right? More painful is that I sent a couple facelift cars to the crusher a while ago, and forgot to pull these sensors off.

 

[mike52787]

The damage





And the repair, you can hardly tell! Temporary... Until I forget and it becomes permanent