[MrEnergyCzar]

2012 Volt. Turns out it was not the infamous coolant sensor but the Mass Air Flow Sensor and wiring harness needed to be replaced. Labor and parts were covered under the GM Major Guard extended warranty. After that was done, new codes were thrown. Are they all related to the first code listed? Here they are per Onstar:

P043E The Emissions System is not performing as expected. An issue has been detected in the Evaporative Emissions System which prevents the escape of fuel vapors from the gasoline in your fuel tank and fuel lines. The following may correct an evaporative emission malfunction: - Check that the fuel cap is fully installed. If you determined that the fuel cap was not seated properly, a few driving trips with the cap properly installed should turn the light off. - Ensure that good quality fuel is used. If fuel below vehicle standard, as noted in the owner manual, was used, it may require at least one full tank of the proper fuel to turn the light off. If these conditions do not apply or are not corrected with the recommended actions, please have your vehicle serviced.

P0AC4 The electric propulsion system is not performing as expected. Please service within 7 days. There is another trouble code in the Hybrid Control Processor, which may or may not be active at this time. If no there code is found, service within 7 days.

P1AF0 An issue has been detected in the Engine and Transmission System

P1AF2 An issue has been detected in the Engine and Transmission System

P1AF4 An issue has been detected in the Engine and Transmission System. Please service within 7 days

P1AF6 An issue has been detected in the Engine and Transmission System. Please service within 7 days

P1E1C The electric propulsion system is not performing as expected. Please service within 1 day

P1E22 The electric propulsion system is not performing as expected. Please service within 1 day

 

[DonC]

Sorry to hear you still have a problem. My issue was the wiring of the harness. No further codes or messages. My guess is the repair wasn't done correctly and/or you needed a update to clear the codes and that wasn't done. Either way or something entirely different it will get fixed. FYI mine was fixed under the Voltec warranty. So interesting how these things get coded.

 

[MrEnergyCzar]

Yeah, he did some updates too, I even rode tested the car with the tech. He has to re-chase the lost isolation which I know nothing about. I'm concerned because he said it could be mice eating wires which makes me nervous since, magically, that would make me liable for both time and labor. Neither Voltec or Gmpp would cover mice. A squirrel nut was found in car. It's parked outside.

 

[DonC]

Hard to see a rodent eating a mass flow sensor. Sometimes they will gnaw at wiring for some reason. Usually it's RVs parked in storage areas. Should have been recognized when the repair was made.

 

[MrEnergyCzar]

Don. He's thinking mice could have got into what's under the large power inverter cover when looking at the right side under the hood. The mass flow sensor was just faulty and replaced, this is a new set of codes.