P0455 & Gas Cap Question

[Robert]

For everyone that has had a P0455 (Evaporative Emission Control System Leak Detected (gross lead)), has anyone had the error when it wasn't your gas cap? I've gotten this code last week, I cleared it and got it again this morning. My gas cap seems fine but who knows. All of the references I have found for this codes seem to point to the gas cap however that isn't the only thing that can casue the error. I just wan't to see what other problems people have had that have set this code. I have looked at the hoses from the gas tank to the charcoal canister and nothing seems amiss and I do not smell any gas to indicate a leak so I am hedging towards the gas cap. I did just get my emissions tested about 3 weeks ago. I know they check for presence of lead in the gas tank, and now I am wondering if they tested my gas cap for sealing ability. Maybe somehow they weakened the spring. I think I'll try and see if my Wife's cap will fit from her '93 Sable when I get home tonight before actually buying a new cap. I hope it is the cap, since i would hate to spend $20 on a new one only to have the code come back a week later.

The error code means that my fuel lines to/from the charcoal canister are not holding a vacuum.

 

[gg97]

I don't know if you are still having your problem, but my 97 set the same code. The dealer tried to tell me that I filled the gas tank with the motor running. The light came on when I was on the highway.

They did a smoke test to check for leaks in the hoses but they were fine.

They wound up changing the evaporator valve.

I hope this takes care of it.

 

[Opera House]

442 small evaporative leak

That is an old post! I traced the evaporative leak to the purge solenoid on the charcoal canisters over the spare tire on my 97. I removed this assembly and found the solenoid coil totally rusted through. Taking it apart further found the valve plunger stuck from rust anf the filter screen totally clogged. The clogged screen is why I didn't get the large evaporative leak. Part is # 9F945 cost $36. You can blow through this valve and it only closes when power is applied to the coil. The Haynes test seemed inaccurate. Maybe more of you will have this rust problem. Seemed quite severe for the age. I think this part geta a lot of water spray. Also noticed that the rear axle rubber vent hose broken off at the axle from bending stress. Time to check this before you back those boats into the water