P0496

[TJ1810]

just joined, this forum is amazing for all things related. So thank you to everyone on here.

Currently having trouble chasing a code. It’s a p0496. I was getting tighten gas cap as well in the beginning. And trouble fueling. Shop did a new canister and blew out the lines. Fueling not an issue anymore. Did the gas cap(oem) still no changes. So purge valve was next. Did that and the tighten gas cap never came back on, been a month. BUT check engine light still persists with the p0496. I keep reading it’s not related to the purge vent valve by the canister. But that, and the fuel pressure sensor on the tank would be the only other culprits? I’m not having any symptoms. And the smoke test found no leaks.

Any and all suggestions are helpful

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I'm wondering if the shop got all of the charcoal pellets out of your fuel system when they blew it out. Often, when the pellets get into the lines, the gas tank needs to be dropped and entirely cleaned out, to stop it from occurring again.

Curious, when you fuel the truck, do you remove the gas pump hose as soon as it hits the first automatic shutoff, or do you try to squeeze some additional gasoline into it, to top it off? Most evap canister pellet escape issues are cause by this practice of topping off the gasoline fill.

Other members of this Forum much more knowledgeable than me in troubleshooting this issue will chime in.

 

[Doubeleive]

just joined, this forum is amazing for all things related. So thank you to everyone on here.

Currently having trouble chasing a code. It’s a p0496. I was getting tighten gas cap as well in the beginning. And trouble fueling. Shop did a new canister and blew out the lines. Fueling not an issue anymore. Did the gas cap(oem) still no changes. So purge valve was next. Did that and the tighten gas cap never came back on, been a month. BUT check engine light still persists with the p0496. I keep reading it’s not related to the purge vent valve by the canister. But that, and the fuel pressure sensor on the tank would be the only other culprits? I’m not having any symptoms. And the smoke test found no leaks.

Any and all suggestions are helpful

did you use oem parts? or aftermarket? some of the aftermarket parts are complete garbage.

 

[Fless]

I keep reading it’s not related to the purge vent valve by the canister.

Note that the (rear) vent valve is not a "purge" valve. Using both terms together in this context could be confusing.

It would be helpful to know what you're working on. Consider adding some vehicle info to your signature: year, make, model, engine, etc.

As an example of the detailed info that can be found on www.charm.li, I've added a link to the diagnostic path for that code for a 2011 Tahoe. If you use the link, you can find the similar diagnostic path for yours by using the links at the top of your browser window.

P0496 — 2011 Chevrolet Tahoe 2WD V8-5.3L Service Manual | Operation CHARM

Detailed repair manual for the 2011 Chevrolet Tahoe 2WD V8-5.3L.

charm.li

A purge and seal test might show a clue or two.

There was also a thread on here about what the fuel tank pressure sensor readings should be, at atmosphere. If I can find that, I'll post a link to it. A bidirectional scan tool that can read live data would be a useful tool.

EDIT: different evap code but read the thread below and note the informative video in post #3 (GoTech Wells CounterPoint):

Fuel Tank Pressure Off - SOLVED

Got the P0446 code on a 2006 Tahoe so started the Evap Mystery Game. But since this truck is new to me recently and I haven't done any evap system work on it yet just decided to replace the 3 main parts that go wrong. Purge valve, Vent Valve, and the canister. Bench tested the solenoids and...

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