This thread sounds very close to what I am working on currently. I have a 1996 Volvo 850 Turbo Sedan, successfully completed an engine swap 6 months ago with the same engine. Upgraded to a brand new 16T turbo, IPD RIP Kit. 6 months later I am battling knock sensor issues. Long story short, diagnosis from Volvo Dealer says my ECU is shot and keeps throwing the P0326 knock sensor code. I have heard that the only difference between a 96 Turbo and 96 T5-R is the ECU. Does anybody know if I could find a used ECU from a 96 T5R, drop it in my car, and be good to go? I have also read the ECU part numbers are picky if your car has an EGR or not. My car does not have an EGR, so would anybody know exactly what I could put into this car? Since I need a new ECU anyway, why not upgrade a bit? (I am not ready to spend the $700 to have IPD map my ECU, especially if it is already fried.....)

 

I highly doubt your ECU is fried. The IPD map will have more power than the T5-R ECU. Have you replaced the knock sensors?

 

Replaced the knock sensors with the updated service kit, where you have to splice in the wires and make new connectors and all of that. Torqued them to 15ft/pounds on the block.

I actually just re did this job, thinking the actual knock sensors were shot.

I have been trouble shooting this for a while now, hence why I brought it to the Volvo dealer (only time I have done that in my history). They were able to go through this checklist of 25 items (valve timing, checking the wiring of the knock sensor upgrade service kit, checking the knock sensors themselves, etc). The last thing in their VADIS system was to "replace ECU".

The mechanic there had a buddy with my same car. He came down to the shop, they put my ECU in his 96 850 turbo - same check engine light and codes for knock sensor (just before his car had no CEL or codes). They put his ECU into my car - it ran fine, no codes. Then they put my ECU back into my car, and the code came back.

This was their diagnosis, they say they don't have the equipment to check/test the ECU (Volvo dealer just replaces parts instead of testing them), but by doing this swap it kind of backs up the thought that the ECU is fried.

It makes sense to me, anybody think this is bogus or something?

 

If you can swap the ECMs back and forth and the problem follows the ECM it's pretty hard to argue with it being anything else. Even more so since you've followed the diag tree and it's lead you to the same component.

What about an ARD instead of IPDs ARD Blue

 

You know, the codes are stored in the ECU so unless you cleared them then the test was not valid. If you did clear them then your test is solid.

 

hmmm great point! It can store the code in the ECU even with no power, and it is out of the car?

When Volvo calls me back I will have to ask him if that is exactly what they did. If they cleared the code, swapped the ECU and it went back on in the "good" car, then maybe the ECU is shot. If they didn't clear it you are saying the code will just follow from car to car no matter what.

I don't know anything about IPD vs. ARD, at this point I just would love to get a solid running engine, with no CEL, that won't destroy itself again as my last one did from pre-ignition/detonation. This is also my daily driver, so it stinks to have it down and rely on friends for rides....

 

So this code is creeping back into my car again, 16 months with no problems and being able to run the car hard whenever I wanted to. This time around it is P0331 - Knock Sensore Bay 2 (last time was Bay 1).

Anybody know how to test the updated knock sensor kit? I can only find data online how to test the old kit, before the replacement parts.

Last time I fixed the issue by buying a new ECU - the Volvo dealer said "all options were exhausted, ECU is fried" and tried to sell me one for $400. I got one for $75 from a Volvo parts place near Denver. Has worked beautifully ever since popping that ECU in.

Hard to believe the brand new updated knock sensor kit would die within a year, when the factory ones lasted 12+ years??