2001 C70 ECM-3300, 3310, 3330, 3340

JIMSAUTO07 · Post by **JIMSAUTO07** » 10 Dec 2018, 15:11

Hello all!
I have a 2001 C70.
I replaced the ECM due to a no start concern, it also would not communicate.
I had xemodex transfer the software from my old computer to one they supplied (not matching part numbers)
Since then, the vehicle does start, communicates, and it runs well. The only trouble is after reaching 1500 rpms it generates trouble codes for ignition coil circuits on cylinder 1,2,4,5 but not 3. I have checked grounds, powers, and signals going to and from ignition coils with no problem found. We have swapped cylinder 3 ignition coil to different cylinders to see if one of those trouble codes would disappear but they do not.
Xemodex has been helpful but they do not believe it to be an ECM problem, I am hard pressed to believe its not. As I said, the engine runs great. Every so often it will generate a trouble code pertaining to the ETS lamp failure, so xemodex did a remote software upgrade. But it also still returns.
I am running out of options here.
Is anyone familiar with this problem?
Thank you!

Post by **abscate** » 10 Dec 2018, 15:15

I would try a wholesale replacement of coils and Volvo plugs, occasionally we get hogh rpm misfires caused by pickiness of parts here. I agree with Xmodex that a ECU diagnosis is unlikely here

JIMSAUTO07 · Post by **JIMSAUTO07** » 10 Dec 2018, 15:23

It has Volvo spark plugs that have maybe 20,000 miles on them and all bosch coils. There has not been one actual misfire felt.
You can clear the codes, rev to 1500 (with ease and smoothly) in park and boom the codes are there, no fail. If you let it idle they do not set.

EngineeringBloke · Post by **EngineeringBloke** » 10 Dec 2018, 16:51

Are you sure the ECM is seated properly with the sliding strips at the ECM base in place? Did you use the official ECM removal tool when replacing the ECM?

Post by **abscate** » 10 Dec 2018, 18:00

Moved from P2 forum. Remember the C70 carries the P80 chassis into 2004?

JIMSAUTO07 · Post by **JIMSAUTO07** » 11 Dec 2018, 06:10

Yes we used the OEM tool, and also cleaned connections and used contact enhancer

Post by **abscate** » 11 Dec 2018, 06:50

I think you are down to either the ECM or the wiring harness from coils to ECM by your troubleshooting process.