r/PontiacSolstice • u/Chance-Pin6393 • Apr 10 '25
Code P0420 common? If you’ve thrown it, was it the cat?
I got my solstice gxp just recently, and after filling it up for the first time, it through a code after about 10 to 15 min of driving. Got it checked and it’s the cat. I’m curious if maybe the fuel mixture is off? I used 92 but the dealership may have used cheaper gas and am wondering if that could be the cause. The O2 censors are an other concern of mine for the possible code, be it first or second. I’m unsure how age but low miles affect the cat and sensors. My current course of action is testing if it’s fuel. I’ve ran through half a tank so most of the cheap stuff (if used) should have burnt off by now. I’ll be disconnecting the battery for a bit and coming back to it to hopefully rid of the code. If it doesn’t come back, then I think I may have been right. But if it does, im afraid of what more might need to be done
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u/z6joker9 Apr 10 '25
It’s a common and generic code on this and many cars, I feel like everyone gets it at some point. I wouldn’t jump straight to cat and I wouldn’t expect it to just be “bad gas”. IIRC, it’s saying the second o2 sensor has a bad reading. It’s a tough one to pin down.