P0455 code
Thread Starter
Heel & Toe
Joined: Jan 2017
Posts: 22
Likes: 3
P0455 code
04 vette keeps throwing this code. I understand it to be a "massive" leak in the Evap system, usually due to bad seal on gas cap. Replaced the gas cap with OEM cap and still threw it. Very inconsistent tho. I understand the system checks for leaks each time the car is started. On the first time it detects a leak, it stores the code. On the second time, it throws the code. On my car, I can start the car 25 or 30 times, maybe more, before it throws the code. If this code relates to a "massive" leak, wouldn't you think it would be detected every time the car was started....if it is truly "massive". I know there is only a few things to check and replace if necessary with the last being a smoke test for the evap system lines, but I am wondering if the inconsistency of the code appearing points to the failure of any particular part. Also....I live in a state that doesn't require emissions test so I have just been resetting the code until I can figure this out. Is it ok do to that without causing any harm? There s no decline in performance, this thing hauls....thanks for the help.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
A loose or bad gas cap usually sets a MINOR LEAK code BUT,, examine the cap O Ring gasket and see if its damaged or missing. Should be a nice fat shiny black O ring in the cap. If its cracked or missing, just get a new cap from dealer.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
All that left is to jack up the car and inspect the Evap Emiss System plumbing.
NOTE. There's a small flexible vacuum line on the drivers side of the intake manifold that goes to the fire wall area. It can and does crack. That would cause a loss of vacuum to the tank.
Give that a look see:
NOTE. There's a small flexible vacuum line on the drivers side of the intake manifold that goes to the fire wall area. It can and does crack. That would cause a loss of vacuum to the tank.
Give that a look see:
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The OP of this thread has not been on the forum since 6/30/18 so chances of him responding is slim. Probably best to start a new thread if you are having the same issue as the OP and see what advice you can get.
Moving this to C5 Tech and closing this thread.
Moving this to C5 Tech and closing this thread.
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