I just got my speed sensor replaced, the hub cleaned and "fixed" whatever that means. 2 weeks later: The brakes pump and the abs comes on when I push down on the brake pedal to stop, and the abs/bas lights come on intermittently, with no regular pattern. Does anyone have any suggestions? I'm tired of having mechanics "fix" it, and paying $1,000 every time it goes in for the same problem.

 

There are ABS sensors that monitor the wheel rotation. I would imagine that why they were working on the car they probably damaged these sensors. I would look into that and cleaning those sensors.

 

c230 Pumping Brakes.

Reply: Assuming your wheel ABS sensors are working....then it could be the brake light switch. I had the same problem and changing the switch solved it. Do a search on this forum. Just type in 'Brake light switch'.

 

Thanks very much. I got both speed sensors replaced, and they cleaned the hubs. The brakes still pump when I first turn it on and back out of my space, and when i brake the first time in drive. I took it to the mechanic, and they found nothing wrong with it. They checked everything else, but nothing seems to be a problem. And the lights don't come on when it pumps. Would it have anything to do with the abs control module? Mercedes dealership said I had to replace it, but I think it's a crock. Also, where can I get cheaper good quality shocks other than the dealer? The place closed where I normally go, and having worked at autozone, I know their parts are low quality.

 

Brake light switch is a few bucks and an easy replacement. You really can do it yourself.

 

I have a 2009 SL550. Recently, the primary keyfob I use fail to start the car although it can unlock the door. The error msg shown on the display dashboard is "ABS and ESP Inoperative. See Owner's Manual". I replace both batteries but still can't start the car. I called the MB shop mechanic and he told me to try the less used keyfob. To my surprise, it actually works. Eventually, I learned that there is a life span on the chip in the keyfob on how many times it can start the car. Now, I just need to get a new keyfob.