[jayoldschool]

CEL illuminated yesterday on our 2015 Volt. I had my scanner, but told my wife to check it with OnStar. It's the P043E code. Car was last fueled in March 9th, 26.8l of 91 no ethanol. It's never been overfilled, and there has been no smell. If it wasn't under warranty, I'd check the cap and reset the code, but I'll let the dealer take care of it. I see quite a few other members have had the same code pop up. Wonder if there was a bad batch of solenoid vents?

I'll update this thread once it goes in...

 

[mpmoore1979]

This is most likely due to a bad evap vacuum pump. Had one about a week ago with the same code and I found the vacuum pump is engaged but will not pull a vacuum.

 

[jayoldschool]

CEL went out on Tuesday, we were scheduled for dealer yesterday. Made my wife take it in anyways. At first, they tried to tell us that "light is out, no problem". I reminded them about the historic code, and explained that they need to check the EVAP pump and likely run a smoke test. So, that's exactly what they did. Guess what? Bad pump and bad valve. Parts 22865478 and 25949410.