[MrEnergyCzar]

Question: 2012 Volt. Is or can the P043E code be related or trigger the 7 other codes listed below? In short, I got the P043E code and the 7 others (see below) along with check engine light after getting the mass flow sensor and wiring harness replaced. I removed and put back the gas cap, drove, and a day later the check engine light went off. Onstar now says (I confirmed it 3 times with Onstar) that all 8 codes are gone and there are no codes. I want to know if the fuel vapor code (P043E) can trigger all the other 7 codes shown below. I do not know if Onstar would pick-up what a dealer would in terms of codes but don't want to unnecessarily bring it to the dealer. Thank you.

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. -
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

 

[Steverino]

There is a PDF of the fault codes and what they mean in our Newcomers FAQs, specifically in the "Problems/Issues, Driver Warnings or DTCs FAQ's > GM Manual with all DTC/Trouble codes for the Volt.

If you look there you'll find that this is related to the Evaporative Emission System Leak Detection and it will list related codes at the end of the "Enable Conditions" column. It's a long, multi-page column.

 

[mpmoore1979]

I do not see ant relation between the codes that would cause a P043E code to set. I looked at the mass air flow sensor wiring and the evap system wiring and there are no shared wiring circuits between them. I would keep driving the car until the code returns before going any further on any diagnosis for this code. I have only seen this code one time and had to replace the evap leak detection pump to repair the issue.
Why did you replace the mass air flow sensor and wiring? Was it for a P0111?

 

[MrEnergyCzar]

@mpmoore. The mass air flow sensor was replaced as a result of Service High Voltage Message. It wasn't triggered from the coolant sensor.

 

[mpmoore1979]

There should be no relationship between the Mass Air Flow sensor and the high voltage system. Since I am not working on the car, I would not be able to tell why they would have to replace the MAF and wiring for a service high voltage system error. There is a ECM update for a dtc p0111 which is for the MAF.