Code P0455
Thread Starter
Burning Brakes
Joined: Aug 2010
Posts: 1,194
Likes: 76
From: Great River NY
Code P0455
My CEL lit up; code was P0455. I re tightened the gas cap, cleared the code and all was fine. Two weeks later, same thing happened. Replaced cap with a new one, cleared code and it was normal. Two weeks later, same code appeared. Any ideas as to my problem?
Heel & Toe
Joined: Nov 2015
Posts: 16
Likes: 0
I am having the same issue...however my check engine light has not gone out yet. I do not drive my car much to begin with but wondering the same thing???
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
One of the evap solenoids would be my first guess. There's one near the engine and another near the tank. Not sure the difference on what does what, but I'd start with those.
Just googling that code and c6 corvette and there are tons of threads that should get you pointed in the right direction. Seems like a pretty common issue.
Just googling that code and c6 corvette and there are tons of threads that should get you pointed in the right direction. Seems like a pretty common issue.
Thread Starter
Burning Brakes
Joined: Aug 2010
Posts: 1,194
Likes: 76
From: Great River NY
One of the evap solenoids would be my first guess. There's one near the engine and another near the tank. Not sure the difference on what does what, but I'd start with those.
Just googling that code and c6 corvette and there are tons of threads that should get you pointed in the right direction. Seems like a pretty common issue.
Just googling that code and c6 corvette and there are tons of threads that should get you pointed in the right direction. Seems like a pretty common issue.
Heel & Toe
Joined: Jun 2012
Posts: 17
Likes: 2
Do you also have code P0449? I used the fuel vent solenoid DIY to replace mine yesterday -
https://www.corvetteforum.com/forums...49-w-pics.html
https://www.corvetteforum.com/forums...49-w-pics.html
Advanced
Joined: Sep 2016
Posts: 76
Likes: 10
P0455 is a large evap leak. The engine mounted solenoid is the purge valve, normally closed commanded open to purge vapors collected in the charcoal canister. The rear solenoid is the canister vent valve, normally open commanded closed during an evap monitor cycle. During monitor the vent valve is closed and the purge opened until the desired tank pressure is achieved then closed to effect a sealed system while the PCM monitors tank pressure degradation vs time via the pressure sensor mounted near the top of the tank. The PCM will then report the appropriate code if there are any based on the size of the leak. Vent valves on many GM vehicles have a high failure rate. The purge valve is easily tested. Any large hose leak will also produce P0455.
Heel & Toe
Joined: Nov 2015
Posts: 16
Likes: 0
So if the gas cap does not correct the issue, which direction would be best to take first?
P0455 is a large evap leak. The engine mounted solenoid is the purge valve, normally closed commanded open to purge vapors collected in the charcoal canister. The rear solenoid is the canister vent valve, normally open commanded closed during an evap monitor cycle. During monitor the vent valve is closed and the purge opened until the desired tank pressure is achieved then closed to effect a sealed system while the PCM monitors tank pressure degradation vs time via the pressure sensor mounted near the top of the tank. The PCM will then report the appropriate code if there are any based on the size of the leak. Vent valves on many GM vehicles have a high failure rate. The purge valve is easily tested. Any large hose leak will also produce P0455.
Heel & Toe
Joined: Nov 2015
Posts: 16
Likes: 0
I am not getting this code...only the P0455
Do you also have code P0449? I used the fuel vent solenoid DIY to replace mine yesterday -
https://www.corvetteforum.com/forums...49-w-pics.html
https://www.corvetteforum.com/forums...49-w-pics.html
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Advanced
Joined: Sep 2016
Posts: 76
Likes: 10
P0449 means that the circuit current is low due to a lack of continuity, easily confirmed with an ohm meter if you can access the vent valve. Troubleshooting the P0455 would begin with a look at all hoses connected to the vapor management system, have you had any recent services? Look carefully there. The vent valve is difficult to test due to location. The purge easy, simply remove the hose with the engine running and see if it passes vacuum, if it is then disconnect the electrical connector and recheck. If it continues to pass vacuum it is defective, normally this will set s code defined as "excessive purge flow". If no vacuum it is good. If I were throwing parts based on experience I would replace the vent valve. If you are prepared to replace it, you can also test it, it should be open and close when 12v/ground are applied across it's terminal.
Advanced
Joined: Sep 2016
Posts: 76
Likes: 10
Lucky me, my car ('08 Z 49K) recently set P0449, then P0455 repeatedly after clearing. I tested as above in one of my earlier post and the culprit was the vent valve. Open circuit in my case, should have been P0449 repeatedly but not the case. From dealer inexpensive but requires "updated harne$$". Bought aftermarket from Advance Auto Parts (had it in stock) Repaired now for 3 tanks of fuel.