I got the check engine light today on my 1998 F150 and had the code pulled. It was p0455 gross emissions leak. I searched here and found it could be the gas cap or solenoid? Should I first get a new cap and then disconnect the battery for four hours and see if this cures it? Is there any problem with doing this to clear the code?

Thanks!

 

Pulling the battery (negative) cable to reset the PCM only requires 10-15 minutes. If you don't want to reset your radio, pull only the 5A fuse listed in your owner's manual for the PCM for the same amount of time.

A p0455 DTC may be due to an improperly installed gas cap, a faulty gas cap or it seal, or any other component in the evaporative emissions system that
is leaking air into the system when the EVAP self-test is run. This icludes the vent solenoid, the canister, or any of the myriad hoses int he vent system.

A garage with a smoke machine will find the leak the fastest...

Unless you are faced with emissions testing, there is no operational imperitive in addressing the fault.

Steve

 

Hi Steve,
I noticed that that gas cap was not clicked into locked position. I decided to just get a new cap for $14 anyway to eliminate possible future problems with the cap actually going bad.

I disconnected the batt for 4 hours (before I saw your post) I just reconnected and the check engine light did not come back on. I hope this was the issue and that the check light stays out. If it comes back on I will return for further trouble-shooting instructions.

Thanks!

 

It may take several days (or even weeks) for the PCM to run the required tests and to fail the number of times needed in order to set the CEL to ON.

Don't get too happy to quickly. My Contour took 6 weeks (in the winter) to finally run the EVAP test.

Steve