P0442

Schematic:

SYSTEM DESCRIPTION
The EVAP Small Leak Test is based on applying vacuum to the Evaporative Emissions (EVAP) system and monitoring vacuum decay. The PCM monitors vacuum level via the fuel tank pressure sensor input. At an appropriate time, the EVAP canister purge valve and the EVAP vent valve are turned on allowing engine vacuum to draw a vacuum on the entire evaporative emission system. After the desired vacuum level has been achieved, the EVAP purge valve is turned off, sealing the system. A leak is detected by monitoring for a decrease in vacuum level over a given time period, all other variables remaining constant. A small leak in the system will cause DTC P0442 to be set.

The EVAP System includes the following components
^ The fuel tank
^ The EVAP vent valve
^ The EVAP canister purge valve
^ The EVAP canister
^ The fuel pipes and hoses
^ The EVAP vapor and purge pipes
^ The EVAP fresh air vent hose
^ The fuel fill cap

CONDITIONS FOR RUNNING THE DTC
^ TP, IAT, FTP, ECT or MAP sensor DTCs are not set.
^ System voltage is between 10-18 volts.
^ The DTC P0440 diagnostic test has Passed.
^ Startup ECT is not more than 4-30°C (39-86°F).
^ Startup ECT is not more than 8°C (14°F) more than IAT startup temperature.
^ Startup IAT not more than 4-30°C (39-86°F).
^ Fuel tank level is between 15-85 percent.
^ BARO is more than 75 kPa.
^ IAT is less than 30°C (86°F).
^ TPS between 7-35 percent.
^ VSS below 129 km/h (80 mph).

CONDITIONS FOR SETTING THE DTC
A vacuum decay condition indicating a small leak is detected during the diagnostic test.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the first trip in which the diagnostic test has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF during the first trip in which the diagnostic has been run and Passed.
^ The history DTC will clear when the PCM turns off the MIL.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
The following conditions will set DTC P0442:
^ Loose or malfunctioning fuel fill cap
^ Damaged EVAP purge or vapor pipes
^ Damaged EVAP fresh air vent hose
^ Malfunctioning EVAP vent valve
^ Damaged EVAP canister
^ Leaking fuel tank, fuel sender assembly O-ring or pressure relief valve
^ Leaking fuel filler neck or seal

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

If the condition is intermittent refer to Intermittent Conditions. Intermittent Conditions

Diagnostic Chart (Part 1 Of 3):

Diagnostic Chart (Part 2 Of 3):

Diagnostic Chart (Part 3 Of 3):

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
4. This test verifies that the EVAP purge valve can be commanded ON and OFF.
5. This test verifies that the EVAP vent valve can be commanded ON and OFF.
10. Refer to the information supplied with the EVAP pressure/purge diagnostic cart on proper setup and adjustment procedures.
11. With pressure applied it may be necessary to disconnect the EVAP lines at the components to verify that a line or component is not restricted. A restriction would prevent a vacuum (or the step 9 test pressure) from forming in the fuel tank.
24. An EVAP pressure sensor that does not correctly respond to vacuum (or pressure) will cause this DTC to set.