Transmission Problem- P2500 [slipping when accelerating]

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HarpreetSingh

Active Member
Joined
Nov 10, 2013
Messages
83
Location
Gants Hill, Essex
Car
S55KL AMG (W220)
Good evening all

It appears I've experienced the wrath of the common P2500 fault on the W220's where the transmission slips while accelerating. The symptom that alerted me to this was throwing it into neutral only last week when I had been going over 70mph, it would put it back into gear again at its own accord when it was around 30mph. No warning lights and car driving normally so no limp home mode or anything, just drives again like nothing had happened.

Long story short, I went to my local Indy scanned it and produced error P2500. Gearbox oil level was fine, and did abit of digging to find one of the techy sheets from xentry saying that the Electrohydraulic control unit and ETC control unit both need replacing. Fair enough I thought, no harm in me going to Merc aswell and see what they say. So I went down today and they said exactly the same thing only they said it also needs a new harness?! They claim my gearbox ECU Is swimming in oil but that doesn't marry up with the symptoms of the car. My cars driving fine and has no warning lights on? It's just intermittent that's all...

What I want to know is, is it possible to salvage the harness by having them clear it of any oil residue after the valve body and ECU (and seals and o-rings obviously) are replaced or do I need to get a new harness too? They've quoted me in excess of £1200 for the harness alone and claim it'll take 8 hours, while the Indys said it should take no more than 3 according to Merc...

Any help would be much appreciated. Thanks.
 
Lots of posts where the gearbox ETC unit has been opened up and drained of oil followed by a thorough dosing of electric contact cleaner spray, etc then working as it should again.........also, you will need to renew the gearbox pilot bush to stop the oil from tracking up the harness.

Just carrying out the above tasks should be all you need do, no need to replace the harness.
 
Thanks for the swift reply! Does anyone know roughly how much I should be paying for this job? Mercedes benz claim it's an 8-10 hour job?!
 

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