w210 Brake Assist & ABS System Warning

[Paul P]

Hi guys me again with my trusty 10 year old E320CDI (118,000 miles).
On the dash the BAS Brake assist warning visit workshop it also flashes ABS System warning visit workshop, also the orange warning light on the left hand side of the dash is on Bas & ESP warning light, any ideas ? Cheers PaulP

 

[24 VRT]

Do the warnings come on soon after you start off after the car has been standing overnight - but if you stop, cut the engine and restart they don't then come back up?

I had this problem with my '99 E320CDI - coupled with the cruise control not working. After my local MB dealers spent large amounts of my cash trying to cure the problem, it was eventually diagnosed as a battery fault. The BAS ESP and cruise control systems would trigger as a fault if the battery voltage fell too low. A new battery cured the problem.

Unfortunately as my car spends days on end unused, the battery takes a hammering, particulalry in cold weather, and after the same symptoms occured a year later I had to get another battery - but this time I also got a CTEK conditioner which is used through the winter and since then (3 or 4 years ago) no repeat of the problem and the battery performs as it should.

Hope this helps.

 

[Paul P]

Hi thanks for your reply . we had a new battery fitted in November last year.The warning lights come on straight away as soon as you start the ignition and they stay on, then the BAS and ESP start flashing in the centre of the dash. Also I am losing pressure on the break pedal it is full of brake fluid does anybody think it could be the master brake cylinder ? Would that cause all the warning lights to come on Cheers Paul

 

[BlackC55]

You need to have the fault codes read firstly.

 

[alanuk400]

All those symptoms + no cruise control were on the W202 I bought last month, I took a chance on it and changed the brake light switch on the pedal £9 from europarts everything fixed (the brake lights were working with the faulty switch). Its worth the cost of that switch, than paying a hookup on star.

 

[W210 Fan]

W210, BAS and ESP, surely its the brake switch Ollie, had it go on mine

 

[StevenN]

Can anybody give me help in locating the Brake Switch. Needs looking at but how do you get to it?

Cheers

Steve

 

[EDZ649]

It's located at the top of the brake pedal arm. It twists out of the arm and has a wiring plug connected to it. You need to be a contortionist to get to it!

 

[StevenN]

It must be quite a way up!
I have felt my way up the pedal.
Must try harder.

Is there not an access panel or something?

cheers

Steve

 

[kg9]

Hi
Just cured the exact problem on my W202. Estate
Problem BAS ESP came on intermittently so checked voltage etc across the battery - OK
1. Removed lower facia panel on Drivers side. (Watch out for the height adjustment lever and the handbrake release cable)
2. Changed the Brake switch ( £11 from MB)

3. Cured problem for a day

4. Had the codes read by MERTECH Chatham Kent (£30) be careful here as you probably need a STAR system to define the problem properly

5 There were about 4 codes in the ECU. 2 were for the brake switch (its supposed to reset itself but it didn't) 1 was for the steering wheel sensor and 1 was the Lateral Acceleration Sensor. On the estate this is situated in the boot and is an easy change although the bracket holding it it can be fiddly

6. Changed the lateral acc. sensor (£98 inc VAT from MB) and cured the problem

As many have said on this forum it is imperative you get the codes read otherwise you may end up chasing a very expensive tail
Hope this helps