Check Fuel Cap/Check Engine Light
Got an check engine light. Code reads P0455. Found this about a F150:
First, the Canister Vent Solenoid is closed to seal the entire evap system, then the VMV or EVMV is opened to pull a 8" H2O vacuum. If the initial vacuum could not be achieved, a large system leak is indicated (P0455). This could be caused by a fuel cap that was not installed properly, a large hole, an overfilled fuel tank, disconnected/kinked vapor lines, a Canister Vent Solenoid that is stuck open, a VMV that is stuck closed, or a disconnected/blocked vapor line between the VMV and the FTPT If the initial vacuum could not be achieved after a refueling event, a gross leak, fuel cap off (P0457) is indicated and the recorded minimum fuel tank pressure during pulldown is stored in KAM. A “Check Fuel Cap” light may also be illuminated.
If the initial vacuum is excessive, a vacuum malfunction is indicated (P1450). This could be caused by kinked vapor lines or a stuck open VMV. If a P0455, P0457, or P1450 code is generated, the evap test does not continue with subsequent phases of the small leak check, phases 1-4. Note: Not all vehicles will have the P0457 test or the Check Fuel Cap light implemented. These vehicles will continue to generate only a P0455. After the customer properly secures the fuel cap, the P0457, Check Fuel Cap and/or MIL will be cleared as soon as normal purging vacuum exceeds the P0457 vacuum level stored in KAM.
Note that a stuck closed VMV generates a P0455, a leaking or stuck open VMV generates a P1450.
The Canister Vent Solenoid output circuit is checked for opens and shorts (P1451 or P0446), a stuck closed CVS generates a P1450, a leaking or stuck open CVS generates a P0455.
Now how can I relate this to my Ranger? I first got the check fuel cap light. Then about a day later I got the check engine and check fuel cap light together. I replaced the fuel cap, disconnected the battery and reconnected and both lights turned off. After about 4 hours of driving the check engine light came back on. The read out code is P0455.
Can anyone, and I am sure there is someone who can, tell me how to walk thru a test of each solenoid or valve to find it there is still a problem or how to determine that it only needs the check engine light to be cleared now that the check fuel cap is no longer the problem. Pictures would also be appreciated. Thanks