C200k 2001 W203 Engine Warning Light.

[franey]

I bought a C200 kompressor for the GF.
The engine warning light was on at purchase, seller informed me a new MAF had been fitted (VDO)
Tried a replacement MAF and temporarily cured for about 3 miles.

GF took the car to Mercedes Sheffield and they replaced the cam sensor at the front of the engine due to it leaking oil (£210.00), apparently oil had also travelled along the harness so was flushed out.
Fault re appeared after 30 miles so returned to the dealer.
Dealer again cleaned the harness (presumably with brake cleaner) and informed me that they needed to replace the MAF as it had oil on it (£235).
They claimed that they believed this operation had cured the fault.
Some 30 miles later, the engine warning light re appears.
Returned to the dealers.
They then stated that the ECU needed replacing (£400) and if it did not cure the fault then they would reimburse me.

So, awaiting the arrival of the part wondering firstly if the MAF should be replaced with the original (as it did not cure the fault)
Secondly, any suggestions for a remedy, it seems that MB like to throw parts at the job with no certainty of a remedy. If the latter part is fitted then we are into almost £900 for a possible cure.

Is this a common fault?

Help appreciated!!

Thanks.

 

[momomo]

On these kompressor engines i think its a common fault for the cam sensor to begin leaking oil over time and allowing the oil to travel along the loom into the ecu, maf and o2 sensors. If caught early, the cam sensor can be replaced, loom cleaned if not too bad and if excessive oil has not travelled to all the above areas.

People have in the past cleaned the ecu, all contaminated bits and loom of the oil and successfully cured the issue. They are looking to replace the ecu. It depends on how much oil has travelled into the ecu via the loom already before they cleaned harness.

If the cam sensor has been changed this oil leaking down the harness will be cured, now all that remains is to fix all the contaminated bits. This should totally fix this problem you are having.

 

[franey]

Thanks for the advice!!

Where is the problem ECU located please and what does it look like??

 

[BlackC55]

Oil in the Engine control unit is not ideal but it will continue working ok.

The engine loom needs replacing first and a modified section fitted to stop it happening again. Oil in the loom won't disapear. Replace it.

The oil also gets to the lambda sensors and knackers them too.

What are the fault codes etc?

There maybe other issues too...... With this engine of this year there normally is.

 

[franey]

Thanks, not sure of the fault codes, will get it on to star again next week .
Is the loom a modification by MB ?

Also will the ECU clean up with electrical cleaner?

 

[BlackC55]

Thanks, not sure of the fault codes, will get it on to star again next week .
Is the loom a modification by MB ?

Also will the ECU clean up with electrical cleaner?

Yes. The section should have been fitted already.

Yes to the clean up.

 

[momomo]

Yes. The section should have been fitted already.

Yes to the clean up.

I was waiting for you to come on and take over

 

[franey]

Great.
I just checked the invoice:

Magnet: 3£32.60
Plug : £2.40
Brake Cleaner £3.00

No sign of a harness or loom though.

Was it part of a recall or something?

 

[momomo]

I think its called a 'starter line' (the modified section required), off the top of my head so dont quote me. Im not sure if it was part of a recall but after this problem started appearing will the these engines this modified loom was introduced to stop the oil from travelling down the loom.

 

[franey]

I have just checked the car and there is no adapter harness fitted so will address it with MB, also forgot to mention when starting from cold in a morning the engine revs up and down by a few hundred revs until warm.
Would this have any relevance in the matter?

 

[Will]

I think you'll need a new loom as Olly says. It sounds as though the loom is soaked in oil which will almost certainly cause further headaches in the long term with the other sensors/electrical connections, probably best to bite the bullet and swap it at the same time as the other bits for a reliable fix.

I think the additional 'starter line' is a good idea - belts and braces approach, effectively isolates your engine loom from the camshaft magnet should it ever leak again.

Will

 

[franey]

Thanks Will.

Its all getting quite expensive!!

Would not have been so bad had it been diagnosed right first time although I appreciate it is difficult, even with Star to pinpoint a fault like this which is where the experience obviously kicks in.

 

[momomo]

To be honest they should have diagnosed it and carried out the correct procedure the very first time. This is a well known issue so they should have picked up on it straight away.

 

[BlackC55]

To be honest they should have diagnosed it and carried out the correct procedure the very first time. This is a well known issue so they should have picked up on it straight away.

Exactly!!

 

[momomo]

Olly your inbox is full!

 

[BlackC55]

I know.

I keep it that way for a bit. I get so many PM's that it is dificult to keep up sometimes.

 

[momomo]

Ha, ok i get you.

 

[franey]

Momomo you can PM me if you're lonely!!

 

[graham121150]

Interesting, Oil soaked paper was used for years as a electrical insulation, and even today. So electricians, still come across it, in use!! And understand it is used in substation transformers.

So I am surprised, it is causing electrical problems.

Graham

 

[franey]

Since the first post, the car is due to be collected on Monday.
After lengthy investigations and involving MB UK the Dealer has informed us that the light no longer comes on and the fault was a broken wire to the MAF connector plug.

Hopefully this will be the end of it, car will be for sale soon.

Thanks for your input all.