P0442

DESCRIPTION
The EVAP small leak test applies vacuum to the Evaporative Emission (EVAP) system and monitors vacuum decay. The Powertrain Control Module (PCM) monitors the Fuel Tank Pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the PCM 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 PCM 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
^ DTC P0107. P0108, P0112, P0113, P0117, P0118, P0125, P0440, P0443, P0449, P0452, P0453, P1106. P1107, P1112, or P1114, 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°C and 30°C (39°F and 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.

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 PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test ran 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 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 PCM turns OFF the MIL.
^ The history DTC will clear after the PCM 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 J41413 EVAP pressure/purge diagnostic station to pressurize the EVAP system. Move all EVAP components while testing with the J41416 Ultrasonic Leak Detector.

TEST DESCRIPTION

Steps 1-3:

Steps 4-7:

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.