Holy Diver

Hi guys, as the title states, I'm getting this code. It's not really causing any problems other than occasionally the pump will turn off/click repeatedly when I fill up with fuel... this might occur 25% of the time though. I tried fixing the problem a few years ago by replacing the gas cap, purge solenoid, and vent solenoid. I had to remove the tank for the vent solenoid which wasn't the most fun thing to do. None of this worked.

I'm ready to tackle this again and willing to drop the tank once more and would like some suggestions. I heard the canister can be clogged or the lines to it can become clogged. That's about the only thing I didn't change or replace. Should I buy a new canister and swap it out along with a vent solenoid in addition to cleaning the lines? Also, how would I check to see if current to the vent solenoid is sufficient? Thanks in advance!

Lup

A couple of things
- Double check there is not gas in the canister itself. You know the signs that say don't top off? Gas can over fill and leak into the charcoal canister. There should be no liquid in there.
- You need a GM scan tool(tech 2) to send power to the vent/purge to make sure they are receiving power. Also to see pressure changes(explained below)
- This next info is from me working on a Bonneville from hell when I worked at the Pontiac dealer. Nightmares like this you never forget..

You said you have replaced both the purge and vent on this TA. An offen over looked part of the EVAP system is the "fuel tank pressure sensor". This PCM looks at this sensor when it vents and purges. The PCM wants to see a change. If there is no change(or not enough) it will set a vent or purge check engine code. To the best of my knowledge, there is no code that sets for the fuel tank pressure sensor, and that's probably why its overlooked. This sensor is the deciding factor if there is an EVAP leak, or vent/ purge issues.
A long story short, I would replace this fuel pressure sensor. It might think the Vent is bad, when really it's not. I'm showing ACDELCO 16238399. This sensor is mounted to the top of the fuel pump.
My Bonneville from hell had a bad fuel tank pressure sensor and was causing a EVAP leak code to never go away. I talked with GM tech assist and they recommended me replacing that sensor, even though all readings appeared ok. I replaced the fuel tank pressure and it was fixed. I thought you might be having the same issues as I saw with the Bonneville.


Kyle