I have a ECU (engine compartment mounted) from a working same model car. It is the same part number etc as mine. Mine is a 2004 V70, M56 trans and 2.4 normally aspirated.

When I swap in the spare ECU the car cranks but won't start.

Do I have to get the ECU matched to my car? If I do programme it is the programming in the ECU or the car? Meaning can only one ECU be matched to the car at a time?

I haven't the foggiest idea. But let me go out on a limb...

The other components get mated to the ECU and now you have a new ECU. Are the other computers going to communicate with it? The VIN is stored somewhere.

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My back feels better when I sit in a Volvo seat

ECU's of the same part # are interchangeable between cars (both 1991 B230FT) I have owned. Not sure what changes were made in 2004 year.

People have told me a disabler is built into the 2004 ECU and must be programmed at the dealer. Like most I'm trying to avoid that.

thanks

In order to use a used ECU, the donor ECU needs to be connected to the car it is coming out of, software removed, then it can be installed in your car, and you'll need to have the software installed. Needs to be done by a dealer or independent with access to Vida.

ECU came from a wrecker so that's not going to happen.

thanks

In 1999, Volvo started programming parts to the ECU and other computers. Gone are the 'good old days' when anything could be swapped, even between model years. The DIY keeps getting harder and harder...
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My back feels better when I sit in a Volvo seat