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P0455, stuck, please help

713 Views 7 Replies 3 Participants Last post by  jasons99hoe
Try to keep this short but give you a full history (2005 Suburban)

Few months back, wifes car became very hard to full with gas. No engine light on at this time.
replaced purge valve, vent solenoid, charcoal canister, and gas cap over the course of a few days. Charcoal canister had leaked charcoal bits into my evap lines so I used some compressed air to clear the lines.

P0455 comes on (gross leak)

Took the truck into a shop ran smoke test. They could not find a leak.
Replaced fuel tank pressure sensor and didnt fix issue
Mechanic Discovered that the vent solenoid was working intermittently. Replaced again ( I replaced before) but same issue remained.
The auto guy reported the solenoid would stay in the "venting" state and was unresponsive to the snap on tool trying to close it. He would disappear for 10 minutes or so and when he came back it would be working fine. When he tried to run the evap test, the computer would almost freeze up and the solenoid would not be able to close. He has never seen this before, wants me to take the truck to a chevy Dealer. As a note, he tried two different snap on diagnostic tools and same results

Any help here before I have to take this in? I am due for an inspection this month and not looking to spend over $1k at the dealer on this older suburban
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Did the mechanic test for voltage at the solenoid while it was not responding to commands? If the signal is not reaching the solenoid it can not respond and replacing it will do no good. This will give a clue as to where the problem might be.
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