W211. E320 Cdi ABS & ESP Warning

[Avantgarde nut]

Hello all. Having recently acquired a 2003 E320cdi I have an abs problem that I am having difficulty solving. After owning it 3 weeks the dreaded ABS & ESP warning came on. I have limited knowledge but borrow my friends scanner which gave me the fault C143A speed sensor rear right check component. The local garage replaced it but it didn't solve the problem. After reading and listening to advice I replaced it again with a genuine Mercedes part as I believe the first replacement was not an original. I cleared the codes and the fault returns. Any idea where to try next as I have spent £150 on two speed sensors and still have not solved it. Thanks in advance Martin

 

[streethawk]

Get it on a star. Brake light switch is also a culprit.

 

[David404]

Charge BOTH Batteries

Good advice from Streethawk Re getting it into a dealer/Indi and chacking with a Star computer.

Your 2003 W211 will have the SBS break system, it will have TWO 12v batteries. Main battery in the boot and a small auxiliary battery to power the brakes in case of a electrical failure. The secondary (SBS) battery is (I think) located under the pollen filter in the engine bay.

Remove & clean all battery terminals, clean the battery posts and smear with Vaseline or similar. Fully charge both batteries. Observe safe working - disconnect negative terminals first - reconnect last.

These vehicles are famed for their electrical power consumption, batteries in poor state of charge can give all sorts or issues and induce Star codes.

Whilst you have the SBS battery exposed can you see a manufacture date on it? If its >5 years old you may want to consider replacing.

 

[Avantgarde nut]

Batteries checked and both ok. I have a receipt for the big one in the boot and it tests as spot on. The smaller one under the bonnet is genuine Mercedes and tests as fully charged. I think I need to get it on a star to solve the problem. On the odd occasion the abs light doesn't come on the brakes snatch on and the ! warning light flashes. As soon as the abs light comes on the car drives normal


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[OneForTheRoad]

I had this issue recently when I had a go at changing the front wheel bearing . abs esp also lost power steering . I had to finally shell out £190 on a hub assembly . all my faults dissapeared once fitted . maybe food for thought ????

 

[Avantgarde nut]

Solved with a good mechanic. Two rear abs rings and one rear speed sensor. All good now


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