Backstory - my nephew's '02 XC70 (same as a V70 with longer springs) died backing in the driveway a couple days ago. They had it towed to Pep Boys (rolleyes) who say we can't figure it out. Tow car to dealer, who tell them it needs a new ECM to the tune fo $1800, on a car that's worth about that. I called the dealer today, and was told there's no communication to the ECM, and that they've confirmed power and ground to the ECM and that the CAN bus is OK. So, I can't really fault their diagnosis. He had battery issues 6 weeks back and jump started the car quite a few times, so I can see that the ECM may have been damaged but I'm still puzzled how it just died while running.
Here's the question: Can I grab a used $200 ECM off ebay and plug it in without recoding it to the VIN of this car?
99% sure you can.
Ask over on Matthewsvolvosite.com, they're Newby friendly, and you'll get an answer within a couple hours.
From AllData-
"The engine control module (ECM) contains a unique code for each car for the immobilizer. The central electronic module (CEM) checks this code at engine start up. The engine will not start if the central electronic module (CEM) detects an incorrect code for the immobilizer. This means that the engine control module (ECM) cannot be switched from car to car."
Not sure if this means a used one can be unlocked by the dealer with Factory scan tool -
"The engine control module (ECM) must first be "unlocked" using a unique PIN for each car before it can be programmed with a code for the immobilizer. When the engine control module (ECM) has approved the PIN, the code for the immobilizer can be programmed."
Even if it is possible, I don't think the dealer would be interested in attempting it for you. You would have to find an independent that has suitable scanner/software capabilities.
I should add, I know for a fact you can swap ECMs around on the 850s, people swap non-EGR computers into cars equipped with EGR when deleting the EGR, same for SAS equipped cars. Volvo has had OBDII since late '94 on all of their cars, so '94 to '97 is pretty much plug and play, and I know I've read of some using S70 ('98+) ECMs on 850s.
S/V70 is pretty much the same thing as an 850. I don't know if things changed much when Ford got control though. That was around '01.
I don't think there is any way around a new ECM and dealer involvement. The CEM is the 'big daddy' of the computer network, and as such needs to authorize any replacement ECM that shows up in its neighborhood. I believe you should be able to source a used unit and have the dealer do the 'reprogramming' to make the car happy.
Found better info, the ECMs all became "VIN locked" in '99. Sorry, my original statement was assumption based on 850 experience and their close relation with S/V70s.
Seems that most Volvo shops can't/won't "re-VIN" a ECM, you'll have to find a tuner shop that does ME7 tuning i.e. Porsche, Audi, Vw, Ferrari, Volvo, etc.
Looks like you could get away with a ECM swap if you also swap the Electronic Throttle Module, ignition, and keys, from the same car you are sourcing the new ECM from.
