The ABS light stays on, but brakes are okay. What's could be wrong with it. on 1990 Mercedes-Benz 300E

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When coming to a stop, the engine gets rough and the ABS light comes on. The brakes are good, though. What could be wrong? It's a 1989, but the year wasn't here, just 1990 or newer.
(4) Answers
(4) Comments
Overvoltage Relay behing the Battery,ZLooks like a little box usually with a clear flip up lid,open the lid and you will find 2 standard Plastic 10A fuses,One of them will be blown,replace the fuze,car will idle perfectly, ABS light will be gone,Adam
That's correct.......had the same problem. Sometimes the OVR sticks. Give it a flick with your finger and it may free up and the ABS light will go out and the car idle properly. If not replace the Overvoltage Relay
The ABS light means that the ABS system has been shut off because there is a problem with the ABS system, you will just have regular brakes. It should not have much to do with your car running rough at stops.
You need to have the ABS system checked for codes and the rough running also needs to be addressed. How long since your last major service?
The abs light came on once for me when my alternator was going out.
Thank you for taking the time to respond. My apologies for not getting back to you to thank you sooner. My sister died on the 28th of May, and a jillion of illnesses of family members and friends. It's been a rough year. Car is an outward reflection of just how rough it's been.
it is most likely the ovr switch. Just changed mine out , had the same problem and now the car runs perfect. Just had to move the battery a little to get my big paws in there and take one bolt out and unplug it to get it out. Not much to it. takes 10 minutes to do
Thanks for taking the time to respond. It's been months and with all the illness in my family/friends lives, I haven't had a chance to get it fixed. But I'm not having any problems, so I'm sure it's something simple as you suggest. Thanks, again.
I han my car service and my abs light came now is stays on why is that happing