P0442

DESCRIPTION
The evaporative emission (EVAP) small leak test applies vacuum to the EVAP system and monitors vacuum decay. The control module monitors the fuel tank pressure (FTP) sensor signal in order to determine the vacuum decay rate. At an appropriate time, the control module turns the EVAP canister purge valve ON, open, and the EVAP vent valve ON, closed. This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the control module turns the purge valve OFF, closed, sealing the system, and monitors the FTP sensor input in order to determine EVAP system vacuum decay. If the system detects a leak larger than a calibrated amount, DTC P0442 will set.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0443, P0449, P0452, P0453, P1112, P1114, P1115, P1121, or P1122 are not set.
^ The ignition voltage is between 10-18 volts.
^ The barometric pressure (BARO) is more than 75 kPa.
^ The fuel level is between 15-85 percent.
^ The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
^ The intake air temperature (IAT) is between 4-30°C (39-86°F).
^ The start-up ECT and IAT are within 9°C (16°F) of each other.
^ The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

CONDITIONS FOR SETTING THE DTC
The EVAP system can achieve vacuum, but a vacuum decay is detected during the diagnostic test.

ACTION TAKEN WHEN THE DTC SETS
^ The control module will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test ran and failed.
^ The control module will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module will turn the malfunction indicator lamp (MIL) OFF during the first consecutive trip in which the diagnostic has been run and passed.
^ A last test failed (current DTC) clears when the control module turns OFF the MIL.
^ The history DTC will clear after the control module runs and passes 40 consecutive warm up cycles with no failure.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
To aid in locating intermittent leaks, use the J 41413 EVAP Pressure/Purge Diagnostic Station to pressurize the EVAP system. Move all EVAP components while testing with the J 41416 Ultrasonic Leak Detector.

TEST DESCRIPTION

Steps 1-4:

Steps 5-7:

The numbers below refer to the step numbers on the diagnostic table.
4. This step verifies that a failure condition is present.
6. This step verifies that repairs are complete and that no other condition is present.