92 525i computer problem?

you don't say which country you are posting from but

this guy I can fully recommend for repairs or info

Basically the number need to match. But in your case you may find it's just the output transistors that have died, I've seen this before. You can often rob them from a dead ECU and solder them into yours.

I would guess the ignition coils are toast first.

If you can rob them from another ECU, can't you simply go to an electonics store and buy a few? This would give one solder-cycle instead of two ...

Except for the fact they have a Bosch part number and not even Bosch will tell you what they are or sell replacements :-(

Well, it's a transistor. It's probably a power transistor, and it you know if it's a PNP or NPN, finding a suitable replacement should be easy.

Always assuming you can use the info printed on it (minimal) to work out things like the gain.

Haven't had mine apart, but have repaired early Range Rover ones, and they use a Mosfet. That would be my choice as they're rather less likely to short circuit damage. And although it was marked with a house number it was easy enough to calculate a generic replacement.

However, the OP wasn't clear as to whether the fault was to an ignition coil or injectors.

Is there a circuit diagram out there anywhere? The standard way without would be to swap the supposed faulty drive device with a known good one from the same ECU. However, it could also be the trigger circuit and once you get into faulty microprocessors repairs become more tricky.

This site - although in the UK - might be of help. Some very knowledgeable people there and they do re-cons.

Many pretty cheap DVMs will do this for you.

thanks for the help guys.i got a used ecu off ebay and should have it tommorrow.i read that the last 3 numbers are critical and 402 is compatable with 403 and 405.can anyone confirm that?thanks again