Well I just replaced the opti, coil, and ICM. Started the car up and ran like a champ. Shut it down when I got to the store came back and now the car runs like ****. It pops a little at idle, runs bad up the rpms and I get the codes for both oxygen sensors I had headers done, egr as it doesnt have emissions on the LT's. and 1361. Ok were do I start? I ordered a new opti harness because my'n looked a little bad from when I changed it. The car runs strong at first start up but when I shut it down and restart it it runs bad.

If anyone knows what wire to check with a voltmeter LMK so I can pinpoint it down to wheres the grounding.

 

will this work on obd2??

DTC 42 -- Ignition Control (IC) Circuit (Grounded Circuit) -- Clear DTC's. Crank engine for 15 seconds. Does DTC 42 set?? NO-->DTC 42 is intermintent. Yes-->Ignition OFF. Disconnect ignition coil module connector. With a voltmeter on an AC scale, proge ignition coil module connector terminal "B" (white wire) to ground. Crank engine and observe voltage. Is voltage between 1 and 4 volts??

NO: Ignition OFF. Disconnect ECM connector "A". With test light to B+, probe ecm harness terminal A12. Is test light on?? NO-->Faulty ECM connection or Faulty ECM. YES-->Grounded IC circuit between ECM and ICM.

YES: Ignition OFF. With test light to B+, probe ICM harness connector terminal "C" (black wire). Light should be on. Is it??

NO: Open ICM ground circuit.

YES: Ignition ON. With test light to ground, probe ICM harness connector terminals "D" (white/black wire) and "A" (pink/black wire). Light should be "ON" both. Is it?

NO: Faulty circuit from coil to ICM on circuit that did NOT light.

YES: Faulty ICM connection or faulty ICM.

 

The P1361 means the pcm detected no activity from the ICM. Check for shorts or grounds in the ICM circuit. Everything plugged up good?

 

The GM online code listing shows P1361 as specific to a grounded ICM circuit.

 

Any one the the four wires can be grounded and cause the code? If I check for continuity what cable should not be showing a ground? Also could a bad opti harness cause this?

 

A 1361 only sets after the PCM has detected 84 crank revolutions and there has been NO IC control activity. Therefore you can assume the feedback from the opti is working.

You want to focus on the white wire from the PCM to the ICM. If you ohm it out, be sure to disconnect at least one end. You must be careful however if the problem is from being shorted to ground. If you only check from end to end, it will appear good. You should also ohm from one end to ground. In that case, you should read a very high resistance. In the order of meg ohms.

If that appears to be good, remember that when you hook 2 devices together, either of the devices can be defective. One sends output to anothers input. The input device can be sinking the signal down near ground or the output device might not be sending it. It's a good idea to look for the output of the PCM with the ICM disconnected. However, the 1-4 volt rule will not work here since the ICM is disconnected. Use a test light as the source instead of the ICM in that case.

That last item left if you've eliminated the wiring and the ICM, is the PCM. However since the problem occured after you did work on the ICM and coil, I suspect either the ICM or the wiring.

Keep in mind that poor quality coils can destroy ICMs. IF the ICM has a shorted or near shorted input, this could cause the problem you have. I would be suspect of any aftermarket coils or ICMs if you didn't purchase OEMs.

 

Turns out the connectors were a bit loose where the pins go. No more 1361 but now I get missfire on cyl 5!! OMG I can never go without a code.