will ECU's for the same 850 with different numbers work

eboknight · Post by **eboknight** » 02 Mar 2009, 14:24

There are several variations of numbers labled on the ECU's for the volvo 850 year 96. I believe there are 7 or so. I want to know will a ECU with different numbers work in my car. The ECU is coming from the same make modle and year.

Post by **misha** » 02 Mar 2009, 15:24

I think that numbers on the ecu must be the same(BOSCH number).It's like a finger-print.If the cars are same models and same production year,and THE MOST IMPORTANT

-same engine code(b5254s,b5252,etc),then ecu will be ok.You can't put ecu from turbo to base model.

eboknight · Post by **eboknight** » 02 Mar 2009, 20:41

Thanks I was told by a guy at a junk yard it could fry some electrical if the numbers do not match, but he was not sure. He had known of a nissan that the ECU was swapped with different numbers and did fry and it cost over a grand to fix. Whats the easiest way to find the engine code.
just trying to be on the safe side.
thanks eboknight

Post by **misha** » 03 Mar 2009, 17:11

Your engine code should be located on the timing belt cover(it's a sticker).There is some serial number and engine code like b5254s for a non-turbo model.You can see engine code in car's commercial licence(registration).It's written just before engine number.
For example b52524s-123456.
But i think that is EXTREMELY IMPORTANT that ecu's have same BOSCH numbers.

Post by **misha** » 03 Mar 2009, 17:27

EDIT:

For example:B5254s-123456

Post by **VCA** » 03 Mar 2009, 18:03

eboknight wrote:There are several variations of numbers labled on the ECU's for the volvo 850 year 96. I believe there are 7 or so. I want to know will a ECU with different numbers work in my car. The ECU is coming from the same make modle and year.

1996 is a *very difficult* year to match ECU part numbers on. The NA motor (B5254FS) had *three* variants with different ECU P/N's (Bosch LH, Motronic 4.3 or Motronic 4.4). These are *NOT* interchangeable--the variants also account for different emissions. It would be easiest to either a) match the ECU by Volvo part number (should start with an '8') or b) ensure they have the same Bosch P/Ns. It must be from the same year (a '97 should work if P/Ns are the same, but a '95 definitely won't).

...and yes, the pinouts on these ECUs are all different, there is the potential for toasty electronics if an incorrect unit is installed. Also, if the other car has an air pump and yours doesn't--CEL will be on permanently. If the other car *doesn't* have an air pump and yours does--toasted components. Interchange like for like only! Best of luck!

If we had the first 8 digits of your VIN and what kind of gearbox your 850 has, one of us can look up the engine and emissions code and point you in the right direction for interchange numbers.