Codes for cylinder 1,3,5,7 test failure after new ecu in my 07 tahoe

[tashalynn82]

I just replaced the ecu in my 07 tahoe and it will start right up but has rough idle. Zeus shows codes for cylinder 1,3,5,7 test failure. Is this because it still needs the crankshaft variation relearn or could it be something else? Yes the new ecu has the same part number as the old one and has been programmed to my vin

 

[kbuskill]

Crank relearn isn't necessary, it will run fine, but is recommended so the ECU will be more accurate with misfire detection.

1,3,5,7 are all on the driver's side. I would double check to make sure the coil pack harness on the driver's side is plugged into the main harness.

Why was the ECU replaced? What was the original issue?

Also what codes specifically are you seeing? You say "Test failure" but didn't say what test.