Hello All.

My 2008 Pontiac GP 3800 V-6 developed a misfire in cylinder #1, A quality scanner revealed a PO201 ..Injector control module circuit..

After the normal eliminating possibles, change plugs, ohm test and swap injectors around to different locations, injector plug connector replacement, ohm and ground test of the ground wire from ECM plug and eventual replacement of the ground wire, a intermittent miss fire on cylinder #1 remained ...fine when cold, within 10 minutes a miss fire until parked again. Everything is pointing to the Injector control module inside the ECM.. Unless I missed something..other sending units and sensors would trigger miss fire on more that just one cylinder .

So I went out and picked up a used ECM, and stopped in to my local shop who has the flash equipment and we authorized the paid GM subscription for my SN# of my vehicle.... we re-flashed my ECM with no change to the misfire.... Plugged the used supposedly correct ECM into the vehicle... no communication... assuming the ECM was faulty, I returned that ECM for another... plugged it in....No communication... Remember there is no problem communicating with my original ECM, The computer should have at the least identified an ECM..???

Is there an unlock procedure or a Sync procedure for an ECM coming off another vehicle to sync to the ignition/Key chip and or body control module prior to a flash??

We're stumped..

Ideas??

As it turned out: Apparently the used ECM would have required a second subscription to re-program it to the car...
End Result: purchased a re-manned ECM
Pretty easily flash programmed.
Running as good as new.. the miss fire gone!

Sorry we didn't have any input for you. Thanks for letting us know how it turned out!

I didn't see this until today.
I would have asked if the injector code moved. No. ECM or wiring to injector.