I've found that the ECM in my car has been superseded by a new PN which cures a cold start condition. The new part is $2000 but I have found a used one pulled from a salvage car for $225 with a guarantee that it will be functional. I know that a new factory replacement part needs to be "coded" to the car, but my question is this...can I swap out a USED ECM which is from the same year and model as my car without coding?

What is it they code in? Is it related to VIN and odometer readings or just things like option and emmisions issues? If the latter I can confirm the options by tracking the donor car's VIN to make sure it is compatible...Can anyone tell me what will happen if I swap out a salvage ECM into my car without recoding it? No guessing please, if anyone KNOWS what to expect please respond. The car does NOT have a smart key, BTW, it uses the old metal blade "switchblade" style key.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

On ALL 1996 & later MB's in the USA the engine control modules is "married" to the car!

Used ECU's are useless in another car unless it has been "un-married" from the original VIN...coding involves a $$$$ scanner with MB coding capabilities.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

OK, so here's a key question, I was told by the SA at my MB dealer that a used ECM cannot be recoded or reused in another car even if it is the correct part...it makes no sense to me that they can only be coded once - that means if they made a mistake coding it they would have to throw it out and get another $2000 part? I realize the SA's know very little and usually talk out of their a** so I assume this is another case of that but can anyone confirm if a salvaged ECM can be reused in another car if it is recoded?

I have asked them to ask MBUSA if there is goodwill coverage they would be willing to apply given the fact this is a known fault which was supposed to have been corrected back when the car was under warranty (the bulletin is dated 1999). He was doubtful, but before I contact our MBCA liason I need them to at least try to get goodwill to cover its replacement. It's hardly worth spending $2000+ to correct this annoying issue but since it is based upon a defective part that supposedly only MB can supply and install I felt it was worth a shot trying to get them to goodwill it.

__________________
Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

There is 1 company here in the USA that can "un-marry" that ECU..you would still have to have some-one code that ECU to your car.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator