p0451 & p0463

[jmben91]

Any ideas of where to start? My gas gauge went out a week before the car threw a CEL...

Gas cap fits snug & the gasket in it isn't cracked at all. No loose wires under the hood or blown fuses near intake.

Thinking of checking wiring near tank... but not sure of how to access it. Does the tank have to be dropped or can it be accessed from under the rear seat?

If anyone has any suggestions, I would definitely appreciate it!!

 

[acamacho104]

p0463 Might be a faulty sender. Or a short. I've never had to do it on these so idk if you need to drop the tank or not. If it's a sender you'll need a new fuel pump assembly.

p0451 might still be the gas cap, but it could also be the canister or a hose someplace....or another wiring issue.

I hate when it can be an electrical issue, because it could just be a squirrel or small mammal that messes up your day. I guess I'd start by getting it up in the air and checking all the wiring in the area and inspect the gas tank for damage as well.

 

[jmben91]

Thanks for replying

I hope that I can get to it from under the backseat... no videos of a sonic being worked on yet, but it looks like its predecessor (the aveo) had it accessible from under the seat.

I'll see what I can get to this upcoming week/weekend, and depending on what I find I might just either a) live with the CEL, or b) take it to a mechanic. I don't have a smoke machine to test for pinhole leaks or bad valves in the EVAP system, but I could take the valves out from under the hood and test to see if they hold. It's what is under the car that worries me.

https://www.youtube.com/watch?v=c6fik_dqzvQ&t=104s

 

[jmben91]

Update-- pulled out back seat, no fuel pump access door If anyone sees this thread in the future know that you will have to go from underneath to look for problems, not above, unfortunately.

 

[Nucky04]

Any resolution to this? I’m also getting code P0463.


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