Brake faults

[Razi]

For last three days my car has been showing fault messages for three problems, all brake related. It is a W reg (2000) E240 with 134000 miles on the clock. The fault messages go like this:

• ESP Elec. Stab. Prog. Visit Workshop
• ABS ABS system Visit Workshop
• BAS Brake Assist. Visit workshop
• 3 malfunctions

I took it to the 'workshop' the day before yesterday and they serviced it and checked the fault codes etc stored in its computer but found nothing. They reset the whole thing and told me that it would be fine but it did this again this morning. What can be wrong. According to the mechanic nothing seems to be out of order. The car had Service A less than 48 hours ago. The fault codes go away once you switch it off and all of a sudden come back. I have had this situation four times now and 3 times it happened while I was reversing into parking bays. Fourth time it happened when I was driving off but if I switch off the engine for an hour or two, it goes away. Should I worry about it? We are going on holiday next week (leaving Monday morning) and the car will do above 1000 miles in a week, should I worry about these warnings?

Thanks in advance for any input.

 

[brandwooddixon]

This is a common problem with the W210.

The most suspect culprit is the brake pedal switch, a simple and cheap thing to fix. There are other causes, but that is the most common.

I had a similar problem, but for me the warning lights only came on after the car had sat unused for a period, say overnight or the weekend. They would then go out if I ran the car for a few minutes and restarted the engine. It turned out that my battery was dying and couldn't provide enough voltage on startup, having sat idle, to properly run the car's many control unit inbuilt diagnostics.

 

[television]

Yes the brake light switch is the first port of call, at £8.75 and 20 mins to fit you must try that first

 

[Razi]

Is it something serious, would it make any difference to the braking system. I have only one day to have it fixed and then the whole family would be in the car going all the way to Lands End and back and on the way back exploring Devon. One thousand miles with those stupid warnings coming and going. Should I worry about anything? Thanks for the above replies. I am relieved to know that the whole braking system does not need replacing!!

 

[BlackC55]

Whe the warnings show the esp, BAS and abs function will not work.

It take two minutes to fit one. Dealers always stock them.

 

[Razi]

Thank Black555, just popped outside and opened the car. Can't find anything above the brake pedal, apparently there has to be a nut of some sort that holds the switch in place. I can't see anything but plastic with footwell light and a screw that holds the plastic in place. Can anybody please give me step by step instructions on how to change the brake light switch. Will do it first thing tomorrow morning.
Thanks in advance.

 

[television]

Pleas put up the next 3 numbers of the VIN after 210

 

[BlackC55]

Remove the drivers side footwell cover and the switch is under there.(phillips screws) There is no nut its is just a 90deg turn to remove it.

 

[television]

Remove the drivers side footwell cover and the switch is under there.(phillips screws) There is no nut its is just a 90deg turn to remove it.

Thank you young man

 

[Razi]

Pleas put up the next 3 numbers of the VIN after 210

261

I just opened the panels and pulled out the switch. It sticks if I extend the white knob full and makes clicking sounds. Does not come out fully and when pulled to be extended makes clicking sounds. I sprayed some WD40 on it but will change it later. Removal involved removing three Phillips screws, two big plastic ones and pulling the panel out of retaining stubs. I hope putting it back is still a possibility!

Thanks for all the help. Hopefully more people will benefit from the discussion of this very common problem.

 

[television]

Spraying it will not help, the switch is in two parts, the brake light and the BAS pressure pad and it is this part that fails, so nothing to do with contacts

 

[Razi]

Thanks everybody. Popped out to Brentford Mercedes and bought two pieces for £19.40. One spare will sit in the glovebox. Fixed the car in 10 minutes, drove up and down the street and it works fine. Thanks once again. Now my confusion: Should I continue with my independent Merc/BMW specialist who failed to find such a common fault and charged me £60 for running the diagnostics plus £170 for Service A. I have been going to them since 2001 (my BMW days) and have been recommending them ever since. After this fiasco I should change my mechanics. Can anybody recommend a reliable indi in Heathrow area, please? Just to make this thread more informative, here is a link to a US forum with pictures of a brake light switch being changed on an ML:

http://www.benzworld.org/forums/w163-m-class/1166641-ets-bas-warning-light-fix.html

 

[television]

Thanks for posting back with a good result and all fixed.

Your indie did not do you any favours and was expensive for that diagnonsis

A service from MB is only £220 on my SL

 

[grahamwoodward]

Just found this thread - I have a BAS error message (Brake assist) on my 2001 C240. Is it the same as the E240? The diagnostics say its the brake release switch. Should I try the one in the footwell before doing anything else?

Thanks

 

[Naraic]

Sounds like a plan.

 

[television]

I would as well, there is the right code for this

 

[Alex Crow]

Hi Graham,
If the fault does indeed lie with the BAS release switch you have only one option - replace the brake servo.
They are fiendishly expensive from MB, but a S/H one would be much cheaper.
Having said that, the code can come up in error with low voltage issues, so you need to be sure of diagnosis first.

 

[grahamwoodward]

BAS error message C240 (W203)

Alex

My neighbour (who owns a garage) plugged the car into his diagnostic system and the fault was reported as "Brake Assist Release Switch". There are no suggestions of any voltage issues. How would they manifest themselves?

Is it worth replacing the switch or should I just plan another trip to Stowmarket.

Regards

 

[Alex Crow]

The switch in question (BAS release switch) is internal to the servo, and not replaceable.

If the error is constant/recuring, and that is the only fault reported we would do a live data check before replacing the servo.

 

[grahamwoodward]

The fault message is constant and recurrs everytime you start the car.

Is it safe to drive - to work (a few miles)? Merc quote £420 for a servo!