Re: P0442 and P0456PD CEL
Gathered some more information:
This indicates a fuel vapor leak in the EVAP control system. It means a very small leak has been detected. In fact, the leak can be from a hole as small as 0.04" in diameter. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.
Symptoms: You likely won't notice any drivability problems.
Causes: A code P0442 most likely means one or more of the following has happened:
•A loose or improperly affixed gas cap
•A non-conforming gas cap (i.e. not factory/original brand)
•A small leak/hole in a fuel vapor hose/tube
•Other small leak in EVAP system
•Faulty vent o-ring seal
Possible Solutions: With a P0442, the most common repair is to:
•Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
•Otherwise, replace the gas cap, or
•Inspect the EVAP system for cuts/holes in tubes/hoses
The Powertrain Control Module (PCM) at different times performs various tests on the EVAP system. OBD II Enhanced EVAP systems are in place to keep fuel tank vapors from venting into the atmosphere, and instead purges them into the engine to be burned. Regular pressure tests are conducted by the PCM to monitor the sealed system for leaks. The PCM monitors the EVAP system pressure by watching the Fuel tank pressure sensor (FTP). When the sensor indicates a small leak in the EVAP system, this code is set.
Potential Symptoms: There will likely be no noticeable symptoms other than the Malfunction Indicator Lamp (MIL). This is because the EVAP system is a closed system and only controls fuel tank vapors, not engine management.
Causes: Usually this P0456 code is caused by an incorrect or faulty gas cap. Filling the fuel tank with the engine running could conceivable cause this code as well or if the cap wasn't properly tightened. Any of the following could also be the cause:
*A small leak in any of the EVAP hoses or fuel tank hoses
*A small leak in the purge valve or vent valve
*The EVAP Canister may be leaking
Possible Solutions: First, using a scan tool activate the vent solenoid, sealing the system. Then monitor the fuel tank pressure (FTP) sensor. If the system is sealing properly, the number will stay consistent. If is isn't, the pressure sensor will show that as well. If the system slowly leaks, use a smoke machine and watch for smoke exiting the system at any EVAP component. Any where there is smoke exiting the system, that is the faulty component. Do not pressurize the EVAP system with air.
The "PD" is a 'Pending Code' or 'continous monitor' and 'maturing' codes.
Pending Codes: These codes are also referred as “continuous monitor” and “maturing codes”. An intermittent fault will cause the computer to store a code in memory. If the fault does not occur within 40 warm-up cycles, the code will be cleared from memory. If the fault occurs a specific number of times, the code will mature into a DTC and the MIL will turn on.
Originally Posted by MetallicMist
OsirisGuy is correct
Originally Posted by stangaroo
OsirisGuy is right
2002 Mustang GT
BBK CAI - Flowmaster Catbacks - Pro 5.0 Shifter