ESP & BAS Issue?

[JamesCLK320]

Hi There,

I've put a similar post in 'Electronics' but wasn't sure which discussion this was best suited for as electronics seems to be more audio/entertainment. Hope someone can help!

The car i'm having this issue with is a CLK 320 Petrol 2002 (W209).

It's happened twice to me now, i'd be on an average drive of around 30/45 minutes pull up and as i've put it into Park about to leave the car the malfunction menu pops up and says 'ESP Defective, Visit Workshop' & 'BAS Defective, Visit Workshop". I'd turn the engine off, remove the key then restart and both malfunctions have cleared themselves.

So firstly, what is BAS? I understand ESP is traction control. With winter on it's way i'd especially like the traction control to be working.

Secondly, is this likely to be a mechanical or electrical fault and is it expensive to repair or is there a common fault/quick fix for the issue?

Anyone else had or seen similar issues?

Any replies would be greatly appreciated!


James.

 

[Supacool1]

Brake Assist System-You could have worn pads or something like that or a dodgy pad wear sensor.

 

[markjay]

BAS comprises of a small probe inserted into the brake servo vacuum unit - just under the pump - called 'diaphragm travel sensor'. It measures the speed at which you apply the brake, and notifies the control unit. If it sees that you applied it in a haste, it will immediately increase the brake assistance which in practice means that a short but very quick brake pedal depressing could fully brake the car. The idea is that if you depress the brake pedal very quickly you must be in a spot of trouble and therefore a bit of extra braking wouldn't hurt.

The diaphragm travel sensor is easy to replace if it went faulty - but BAS/EPS error messages tend to come up for all sorts of reasons, such as low battery voltage for example, so you should really have the error codes read so that you know what your car things that the problem is.

 

[Vlad]

Can also be a dodgy brake light switch

 

[JamesCLK320]

I took the car to a local mercedes specialist, Star Motorworks in Caversham, who read the fault codes. There wasn't an issue they could find so they cleared the codes and said they were likely old codes that hadn't been cleared that caused the fault.

All free of charge as well, I'd definatly go back to them when I need future work doing, like my up and coming thrust arm bearings.

 

[MercMan1]

Not sure if its the same on the CLK, but I used to have the same problem with my S Class, especially when it rained - as has been mentioned there is a sensor against each wheel measuring the speed of the car, in my case one of these did not have full protection against water and hence when it rained - water went in an shorted the circuit, which made the car think it was going into a spin as one wheel was not rotating at the same revs as the others.

Might not be the same for your car, but worthwhile checking!

Good luck mate!