Engine Light Advice

[coopns]

06 GMC Sierra 105k

Over the past two months I have been getting two codes: P0455 and P0496.

Got code, disappeared for a month, back on about 1 a week now.

Yesterday driving and light went off.

I have replaced gas cap. Not sure what to do next? Leave it? Starting to bug me.

Should I start to replace things and if so, what part should I start with?

Let me know your thoughts.

 

[Ramblejam]

Find it difficult to fill up your tank without the pump clicking off?

 

[mehullica]

You need to diagnose, not throw parts at it. Start with the purge valve & make sure it's not stuck on causing purge when it's supposed to be off & sealed. Use a vacuum gauge in between the canister & purge valve & it shouldn't purge on a cold warmup

 

[coopns]

No I don't think but I will take note next time. Haven't really noticed it but will watch for it.

 

[zzyzzx]

Originally Posted By: mehullica
You need to diagnose, not throw parts at it.


I was assuming that the OP was an auto mechanic, hence the throwing parts at it.

Otherwise I agree, they need to diagnose. This is one of those things where I wish HF had a smoke machine for sale cheap, since it can be a really annoying thing to try to fix.

 

[coopns]

Not a mechanic. Just looking for some ideas, I'm curious.

Any thoughts on why the engine light would randomly go off after being on for 4 days?

 

[Doog]

https://www.youtube.com/watch?v=5XMHC0E85YA

 

[danthaman1980]

Evap canister purge valve, maybe? I had that problem on my Silverado once, a long time ago (only part I ever replaced where the OEM part from the dealer was cheaper than all the aftermarket parts). I remember it threw two codes (don't recall which ones, sorry).

 

[kschachn]

Originally Posted By: coopns
Not a mechanic. Just looking for some ideas, I'm curious.

Any thoughts on why the engine light would randomly go off after being on for 4 days?


Because it is an intermittent fault, and once you go through enough drive cycles with it operating properly the CEL is cleared. EVAP systems have a fairly complex test routine with threshold times that have to be met. It could be that you fluctuate on the edge of what is considered acceptable.

 

[Kira]

I can tell you this: During any time you're being tortured by EVAP related codes/lights remember to refrain from topping off your gas tank.
Let the nozzle click off and leave it. Add no more fuel. See if it clears up. You may see your CEL stay off for increasing lengths of time.
That's what happened with car. Kira

 

[coopns]

Funny Kira I was thinking that as well. I don't know much but just logically thinking someone mentioned the jiggy jig can't think of the name of it on the gas tank. Maybe that gets flooded or overwhelmed? I don't know.

So the codes haven't been back in 3 days.

Just had the scanner tool to confirm. Not those codes but a new code that didn't activate the engine light but I did the scanner 3 times and it came up with a P2A01.

 

[Oldmoparguy1]

Originally Posted By: Kira
I can tell you this: During any time you're being tortured by EVAP related codes/lights remember to refrain from topping off your gas tank.
Let the nozzle click off and leave it. Add no more fuel. See if it clears up. You may see your CEL stay off for increasing lengths of time.
That's what happened with car. Kira

+1

I had a similar issue with my 2013 Dodge GC. Stopped overfilling it and the error finally went away.

 

[coopns]

Any idea on which bank this one is?

"P2A01 Oxy Sensor". Didn't say it on the cheap scanner tool friend had.

 

[toneydoc]

Around here you can take a vehicle to an auto parts store like autozone or AAP and they will check the CEL and read code. They can be helpful in these situations

 

[MrHorspwer]

Originally Posted By: coopns
Any idea on which bank this one is?

"P2A01 Oxy Sensor". Didn't say it on the cheap scanner tool friend had.


P2A01 is bank 1, sensor 2.

As for your P0455... give bulletin #02-06-04-037 a look.