ABS, Brake Assist warnings

[ACCA]

On 3 separate occasions in the last three months or so my 2000 E320 Cdi displayed three warnings about ABS and Brake Assist malfunctioning. Coincidentally when these happened the car was at a standstill or crawling at low speeds in a traffic jam. However, each time these malfunctions cleared themselves after switching off the engine and back on again. No recurrence of the same malfunctioning happened for the rest of the journey. Does anyone have the same experience or know what?s wrong with it. Although I think this could well to do with electrical gremlins when the engine is overheating a bit because of the traffic, my first warning did end up with a brake fluid leak which required the replacement of the entire ABS unit. Any advice will be welcome.

 

[colechelle]

most common fault you are talking about is the brake light swich, cheap as chips and 2min job to replace, on going from that it could be anything from rpm (wheel speed) sensor, to dirty muti plugs on the same, but by reading your thread, "in traffic" on the breaks on and of, first port of call is replace that swich hope some help

 

[malcolm E53 AMG]

I own the same model and year estate. Have encountered the same ECU warnings as yourself on two occasions over the last two months in similar driving conditions. On engine restart the ECU reset and warning disappeared.

The brake discs are completely shot on my car (43,000 miles) and the car is booked in for them to be replaced on Wednesday. I have also taken the advice I have read on this forum by having the brake light switch replaced.
Hopefully this is the most likely culprit.

 

[ACCA]

Hi Malcolm210,

Any recurrence of our ABS-Brake Assist malfunctioning warnings after you had the brake pads/discs and brake light switch replaced? The same problem came back yesterday but as usual rectified itself after switching off the engine. Braking seems to be fine all day.

 

[Keith D]

ABS Light

I have a W124 230E and the ABS light came on the other day, on looking in the hand book it seems the light has a dual function, as, other than a brake problem, it indicates that the battery is low. So got home charged the battery and no further probs. I also examined the fan belt to find it was rather worn and fitted a new one.

Regards

Keith D

 

[Alanm]

Abs

Keep getting the same fault on my SLK 320, MB told me that it could be associated with battery drain, as low voltage, or poor battery, can cause it. They checked the car out and could not find a fault, if it keeps happening I will take it back as it is under warranty, let you know what they find.

 

[jberks]

Hi Malcolm210,

Any recurrence of our ABS-Brake Assist malfunctioning warnings after you had the brake pads/discs and brake light switch replaced? The same problem came back yesterday but as usual rectified itself after switching off the engine. Braking seems to be fine all day.

I can't speak for Malcolm but a new switch cured my W210. That was over 3 years ago and I've never heard from it since. Worth doing if you get the BAS/ESP/ABS warnings.

 

[malcolm E53 AMG]

Hi ACCA, garage replaced discs, pads and brake switch and I havn't had any problems since. The discs were probably beyond the manufacturers recommended wear tolerance so I wasn't sure whether this may have contributed to the problem. However all is well now and the cost of a new switch which is very difficult to check re overtravel is neglegible. If the computerised braking system checks are so sensitive replacement of the switch should be part of scheduled maintenance at 50,000 miles or so. The symptoms you describe were exactly the same as I was experiencing. Hope you get a quick resolution to your problem.

 

[ACCA]

Thanks Malcolm,

I'll have the brake light switch changed as advised in my next B-service. There are still some 3000 miles to go.

ACCA

 

[ACCA]

The malfunction warnings came on very frequently of late. Couldn't bear the annoyance anymore and so went to Cornerstone Garage in Illminster this afternoon. They diagnosed by laptop that the problem was indeed the result of a brake light switch failure. Part and labour inc. VAT came to just under £30. Not bad at all since MB Bath quoted £60 plus VAT for the same job.

 

[malcolm E53 AMG]

Pleased to hear you resolved the problem. The information shared on this forum I have already found to be invaluable. Who would have dreamt a brake light switch could create such problems.