R170 SLK 230 ABS light problem

[Benmac]

Hello, I'm new here. I wonder if you can help.

My wife runs an 03 230K SLK that has been as good as gold since we bought it new for just over 50k miles. On wednesday it developed an issue

The ABS and BAS/ESP lights came on. Car felt fine apart from this. Looked in the manual which suggested this may be down to a low battery. The car had been sat for about a week so I thought this sounded plausible. I hooked it up to a charger overnight. On connecting the charger the voltage seemed OK at 11V but I persevered. Fully charged next morning and the lights were still on.

Took it for a drive and the lights went out. Hmmm, OK. Drove it again later on and it was noticeable that it was holding onto gears excessively (its an auto), during this period whilst at walking pace in traffic it momentarily seemed to brake as if I'd sharply dabbed the brake. Just after this the ABS and ESP lights illuminated again, the gear holding disappeared but it was obviously in safe mode. Just after this the main diagnostic light came on.

Took it to a friendly mechanic who has plugged it in today and it is telling him that there is a problem with the Canbus (I used to work on aircraft with databuses, didn't know the SLK had something that whizzy). Having traced around he can see no obvious visible issues so he thinks it is probably the ABS module although he can't confirm this. He has a friendly BMW/MB specialist he knows so is going to take it there on Monday. I loathe main dealers with a passion, I had a great ex MB and Brabus main dealer on my doorstep but they went bust and the local one is dreadful so I really don't want to have to take the car there.

Has anyone ever experienced this and do they have any ideas? Thanks in advance for any help.

 

[television]

Hello and welcome, to me it sounds like a duff battery, measure the voltage before you start the car, if it is below 11.75 then the battery is no good, though it may start the car, what happens is that one cell goes short circuit and pulls the voltage down.

This low voltage will put all of these lights on. the car running voltage should be 13.8 anything below this and you have battery problems.

The other thing that can do this is the brake light switch

Forget all about modules at this stage, thats just guessing and that goes for CAN Busses too

 

[television]

PS if you do have to buy a battery only get

Bosch,Varta,Banner,Exide,lucas, do not buy a house or Hallfords special Cosco are good prices so are Parts Co and MB comercial

 

[Benmac]

Cool, thanks. The voltage in the battery was definitely less than the 11.75 you mention before I charged it, it is the original one and these days the car does sit around for a good few days at a time. I'm more use to my Lotuses with batteries going duff.

I'll try that with a view to getting a new battery. Certainly preferable to digging around changing bits of the ABS.

 

[television]

Cool, thanks. The voltage in the battery was definitely less than the 11.75 you mention before I charged it, it is the original one and these days the car does sit around for a good few days at a time. I'm more use to my Lotuses with batteries going duff.

I'll try that with a view to getting a new battery. Certainly preferable to digging around changing bits of the ABS.

4 years is the max, owing to the loading on modern cars, when the voltage is low the load on the starter motor drops it further recording a blip in the voltage

 

[Benmac]

Fixed it, seemed to be a combination of things in the end. The battery was indeed a way off best and was losing charge quicker than it should. Replaced that but the lights were still on and refused to be cancelled.

My mechanic then remembered that a couple of the lads from the now defunct Brabus dealer I used to take it to had set up round the corner from him so he took it there. They quickly found that one of the main fuses had gone! Fixing this cured the main diagnostic light and also allowed a diagnosis of the ABS issue as the computer would now say something more than 'CANBUS failed'. Turns out one of the rear speed sensors was broken. Replaced this and all is fine again. Phew.

Thanks for the help!

 

[television]

Thanks for posting back, it all goes to help someone else who is having a hard time

 

[Benmac]

Hmmm, this one continues. The 'bulb out' and BAS/ESP light came back and this time no brake lights! So given the advice on here I swapped the brake light switch. All seemed fine but then the light would occasionally return just after starting it up.

Everything seemed to be fine when it did and a restart would cure it and it wouldn't return. This has gone on for a couple of weeks. On Sunday, I happened to be driving and it came on again just after starting up and this time by a reflection I could see I had no brake lights. Hmmm, switched off and left it for 30 seconds. Back on and still there. Tried again, it went off. Came back on on the short journey home but I still had brake lights.

Took it to MB in Stockport. They first cleared a bucket load of faults from the ECU which annoys me as it has been to another MB dealer a couple of times since the first of these fault codes. Anyway, gave it a good going over and couldn't get the fault to recur. Wife goes to pick it up and half a mile down the road it does it. Back she goes, now with a 'clean' ECU they can see the problem more clearly and have diagnosed the lighting module.

This makes some sense to me as my rudimentary knowledge tells me that this module receives voltages from various lights and puts up the 'bulb out' lamp if one of the voltages is wrong. If its the brake aspect then it puts up BAS/ESP as well to show that its the brakes as these are arguably the most important lights on the car. As such if the module is dieing then it could throw this up spuriously.

Now, before I agree to spend a few hundred getting that module replaced would a simple clean up of a particular set of contacts somewhere be worthwhile?

I must say that MB in Stockport have been very good. Not asked for a penny for the diagnosis work and also when she went back this afternoon took very little persuading to find a C class to lend the wife rather than let her walk to the station on her own.

 

[television]

The first part of your post re the ABS/ESP was in line with the battery being low and a starting blip, as the fault cleared on the 2nd start, these cars do not go that long in the Winter without needing a little charge if the car is not used daily

I know that you have a new battery but it would be nice to know the voltage on it before you start

 

[Uncle Benz]

This thread has been dormant for a while, but was of particular interest to me as I have had an SLK with this exact problem all week now. I believe I have found the root cause, and I bet it is going to be a common one in the future. I will not give anything else away yet, as the new bits arrive tomorrow, and I will know for certain then if I have found it...

 

[television]

This thread has been dormant for a while, but was of particular interest to me as I have had an SLK with this exact problem all week now. I believe I have found the root cause, and I bet it is going to be a common one in the future. I will not give anything else away yet, as the new bits arrive tomorrow, and I will know for certain then if I have found it...

Thanks uncle and I look forward to hearing what you found

 

[Uncle Benz]

Well, after what seems like an eternity of fiddling, the car is fixed!!

The major headache was that the fault was very intermittant, and everytime it occurred, it resolved itself the moment I reached for the multi-meter.

Traced to the main light switch - it also incorporates the in-car fusebox. Every so often the brake lights would fail to come on, coupled with esp failure and bulb failure lamps illuminating. The 12v feed to the stop lamp switch was disappearing at the output from the light switch.

After finally identifying the faulty component, another fault with the same part manifested itself - the front fog lights would fail to come on, accompanied by bulb failure light, only to resolve itself spontaneously.

We are lucky enough to have Star machine, but in this case all we got was a brake light switch plausability error. The car had been to main dealer several times, and each time had a new brake light switch fitted. When the owner queried this, he was told they fail all the time. Not twice a week they don't!

Sometimes the old fashioned approach is required. Slowly slowly catchy monkey!!

 

[D1ngbat]

Having trouble with ABS ETS lights not going out and the speedo not working. Sometimes the fault fixes itself by giving an ETS warning the usual beep and the speedo springs in to life. Just had it down my local garage and they tell me that all the continuity tests are ok and the brake switch is ok. Thing of getting a used ABS control unit from Dronsfield. Dont fancy going down to the main dealer to pay £50 to be told my ABS is faulty.
Any advice gratefully appreciated

Sorry think Iam in the wrong thread my car is a W210 300D

 

[westrock200]

ESP BAS Module replacement

Hi and hello to fellow members.

I have a SLK 200 Komp R170 manaul 2001. I have an intermitent ESP/BAS light. My Autual au 702 reader is telling me the module is defective C1000. Car drives fine apart from this. I have replaced the brake switch as a cheap easy fix. Would anyone know if the ESP BAS module can be replaced by removing from the ABS pump and refitting without reprogramming? It looks pretty striaght forward as explained on the website below. Any advice most welcome. Thanks. Westrock200.

http://www.pelicanparts.com/techart...ent/BRAKES-ABS_Control_Module_Replacement.htm