Code vanishes???
Thread Starter
Pro
Joined: Jan 2004
Posts: 516
Likes: 0
From: Long Island ny
St. Jude Donor '06-'07
Code vanishes???
While driving yeaterday I got a check engine light. Checking the codes I found "PO455" displayed. I cycled through all of the historical codes and deleted the old ones. While doing so I erased the PO455 code as well. I was told that if I did this the current code would reappear. So far, after 30 miles of driving the code has not come back.
Is this normal?
Should I get it over to the dealer who will no doubt tell me he can't do anything if he can't see the code?
TIA
Is this normal?
Should I get it over to the dealer who will no doubt tell me he can't do anything if he can't see the code?
TIA
Burning Brakes
Joined: Jul 2003
Posts: 1,233
Likes: 0
From: Drivin' and Divin' in Seattle
Had you just filled the gas tank? I'm coming up with:
DTC P0455 Evaporative Emission System Leak Detected
It is listed as a GM code but is not listed on the stengel site for Vettes.
It may not come back. Consider it a blessing.
DTC P0455 Evaporative Emission System Leak Detected
It is listed as a GM code but is not listed on the stengel site for Vettes.
It may not come back. Consider it a blessing.
Drifting
Joined: Jan 2003
Posts: 1,453
Likes: 5
From: The Island of Long NY
St. Jude Donor '05
Scott, I would check to see if your cap is coming lose when you hit the fuel release door. You said it may be coming lose. If so I would get another cap from the dealer. Thanks again for the endlinks.
Chris
Chris
Burning Brakes
Joined: Sep 2004
Posts: 815
Likes: 75
From: Lincoln CA
St. Jude Donor '16-'17,'19
I saw the P0455 code on my 2004 coupe one time about 1000 miles ago -- check engine light stayed on. After identifying the code, I reset it and it has not returned. I have not noticed that my gas cap has been loose, but it seems to take very little effort to remove.
Ernie
Ernie
Drifting
Joined: Apr 2004
Posts: 1,937
Likes: 3
From: Jacksonville Florida
I have check engine light came on with P0455 code on my 04. I check my gas cap and it was just hanging on top of the filler tube. I retighten the gas cap and resetted the code - cleared the check engine light.
Race Director
Joined: Nov 2003
Posts: 12,346
Likes: 5
From: Mustang OK
Originally Posted by thevettenet CA
That code is consistent with a loose gas cap, according to my service manual for code P0440, which someone posted had been changed on later models to P0455.
Also, the diagnostics on your car appear to be functioning normal and as prescribed within my '03 GM Service Manual. The PCM monitors the fuel tank pressure as part of the Evaporative Emissions System test. I too believe this may be connected to the loose gas cap problem you reported in your other post. Good luck! 
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
2027 Corvette vs The World: Every Model vs Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
Safety Car
Joined: Dec 2002
Posts: 4,010
Likes: 1
From: SE Idaho
St. Jude Contributor
I believe P0455 designates a large vapor leak in the sealed fuel system. The best thing to do whenever a P04** code is received is to reset, and drive a few hundred miles to see if it resets. That is after you cycle the cap on/off first.
We did some testing a few months ago at the GM Spring Hill Assembly Plant, trying to get a feel for how long it takes for a P04** code to set with the fuel cap completely off. It took close to 55 miles of constant driving to turn on the light, then we reset, and it took another 50+ miles to turn the light back on.
Problems that can cause these P04** codes to set include the fuel cap not on correctly (three or more clicks), incorrect fuel cap, vapor line loose, cabon canister fittings loose or canister blocked. Large leaks usually are attributed to the fuel cap being completely off, the vapor relief line off (there is a tube that runs from the tank to the fuel fill pipe to allow pressure to equalize while you fill the tank), or a vapor line completely off.
We did some testing a few months ago at the GM Spring Hill Assembly Plant, trying to get a feel for how long it takes for a P04** code to set with the fuel cap completely off. It took close to 55 miles of constant driving to turn on the light, then we reset, and it took another 50+ miles to turn the light back on.
Problems that can cause these P04** codes to set include the fuel cap not on correctly (three or more clicks), incorrect fuel cap, vapor line loose, cabon canister fittings loose or canister blocked. Large leaks usually are attributed to the fuel cap being completely off, the vapor relief line off (there is a tube that runs from the tank to the fuel fill pipe to allow pressure to equalize while you fill the tank), or a vapor line completely off.
Last edited by WhiteC5Vette; Oct 29, 2004 at 06:44 PM.