ABS, BAS ESP light and dash warnings - a saga

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DarloDunk

New Member
Joined
Jun 3, 2019
Messages
5
Location
Darlington
Car
CLK 200 Kompressor
Sorry guys but yes, here we go with this old chestnut again!

Bought a CLK 200 Kompressor 2002, it already had the ABS, BAS and ESP lights on. The garage said it would be a £15 fix, so I took the chance. And so the saga begins.

Read the forums, watched the You Tube videos and replaced the brake light switch. It didnt fix the problem. Called out a diagnostic guy, he reset the faults, I drove 5 yards the lights came back on. We went for a drive all 4 wheel sensors were giving data. The faults were all to do with low voltage.

I had the battery checked, it was a bit low on charge, although the static voltage and the voltage with alternator running were OK. Still I charged it up fully. No change.

Next stop independant Merc garage. Different Diagnostic, similar results. He checked the input voltages at the ABS module plug and all were OK. His conclusion was that there was an intermittent fault in the wiring loom or the ABS module was knacked.

On getting home, and knowing a bit about electronics, I decided to buy a voltmeter and check the resistance of the ABS loom to earth, having also bought a Merc wiring diagram. it was OK too.

I have a friend who is a mechanic and called on his help. We bled the brakes and whilst on the ramp checked the ABS rings at the rear (even though they gave correct data) they were OK, no cracks, we cleaned them. Noticed that one sensor seemed a little further away from the ring than the other?

Ordered an ABS module from Ebay.... when it arrived I was all excited until I realised that it was a different model, both end in 132, and I picked the wrong one! Sent that back and ordered the correct one for around £140.

Whilst waiting, I heard stories of after market brake light switches causing problems. So I ordered one from Merc. Funnily enough it was £13 for a genuine part, cheaper from Merc than Ebay! With fingers and toes crossed I fitted it.... Bugger, still the same.

Just to note that lights 9 out of 10 times come on straight away without the car moving. I dont need to say that the steering wheel, left and right trick didnt help.

here I am waiting for the ABS module to arrive, fingers and toes crossed, because if this doesnt fix it, Im running out of options. Other than the lights being on the car drives fine. I will update thread as I go along, with the hope that this will be the go to thread for anyone else with ABS, BAS and ESP problems.
 
Try a new battery! How old is the current one, my bet is the battery is failing
 
^ Now you have your voltmeter, re-check the battery before starting the car. It should read 12.3/12.4V with a good charge.
That should rule out whether you have a battery problem or not. Low voltage, as you probably are aware causes all kinds of problems with Mercedes.


Hope you find a fix for the current fault.
 
what error code is showing?

It might be an EPS fault

I fear it could be a serious (ie expensive fault) - if it was cheap and easy, the seller would have fixed it

I would return the car as it is not of merchantable quality and arguably is not road worthy - it certainly wont pass an MoT with that fault
 
Could the wrong aspect ratio tyres have been fitted front or back = different rolling radius ? Easier to do now with staggered wheel widths ? That will flag up fault codes on ABS, BAS and ESP. What were the fault codes?
 
Thanks responders.... This ABS BAS ESP fault seems to get most Mercedes in right state... Me too! HOWEVER.... The complete ABS Module, Aluminium Block and Pump came. I swapped the modules over and suprise suprise no change, lights still on. Was thinking £140 down still no further forward. Again having time to reflect the first diagnostic guy said there was data from the wheels so it couldnt been them. Ive tried 3 brake switches and an ABS module, so really there wasnt much else it could be??? Today I popped round to my friends, as he has all the tools. I went there to change the ABS pump. I checked the one that came attached to the module I bought and the brushes were ok and it was free running. In the end I had to change the whole assembly, ABS module aly block and pump. Once the new one was fitted, I started her up....no lights.... AMAZING... but needed a longer run just to confirm this wasn't a fluke. Changing the ally block also meant a long thorough bleeding of the brakes. My friend helped using a pressurised bleeding system. All done, all I went, long way around the block....still no lights!

SO the long and short of it was that the original ABS pump was defective.

I've gone through hell to get here, and now its weird having no warning lights and no fault messages! There's a lot that can cause these lights to come on. Start with the easy things first. Then get a diagnositic, which would tell you if it was a wheel sensor. If they are ok, youre looking at the ABS module.... or like me the pump. Ive not had a chance to look inside my original pump yet but I suspect the brushes have gone. If you are brave you can replace these for a few quid, rather then buy a replacement pump.

Thanks everyone
 
what error code is showing?

It might be an EPS fault

I fear it could be a serious (ie expensive fault) - if it was cheap and easy, the seller would have fixed it

I would return the car as it is not of merchantable quality and arguably is not road worthy - it certainly wont pass an MoT with that fault

I agree with you buddy. I think once he knew it wasnt the brake light switch he passed it on. Cost me less than £200 to fix so Im a happy bunny, and love driving my CLK around.
 
^ Now you have your voltmeter, re-check the battery before starting the car. It should read 12.3/12.4V with a good charge.
That should rule out whether you have a battery problem or not. Low voltage, as you probably are aware causes all kinds of problems with Mercedes.


Hope you find a fix for the current fault.
Thank. I got 12.4
 

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