P0442

DESCRIPTION
The Evaporative Emissions (EVAP) small leak test is based on applying vacuum to the EVAP system and monitoring vacuum decay. This diagnosis will detect a leak as small as 1 millimeter (0.040 inches) in the EVAP system. The Powertrain Control Module (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. This allows the engine to draw a small 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 the vacuum level during a given time period. A small leak in the system will cause DTC P0442 to be set.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0107, P0108, P0110, P0112, P0113, P0115, P0117, P0118, P0121, P0122, P0123, P0125, P0440, P0443, P0449, P0452, P0453, P1106, P1107, P1111, P1112, P1114, P1115, P1121, or P1122 are not set.
^ The system voltage is between 10-18 volts.
^ The start-up Engine Coolant Temperature (ECT) is between 4-30°C (39-86°F), but the start-up ECT is not more than 8°C (14°F) more than the start-up IAT temperature.
^ The start-up Intake Air Temperature (IAT) is between 4-30°C (39-86°F), but the start-up IAT not more than 3°C (7°F) more than the start-up ECT temperature.
^ The fuel tank level is between 20-85 percent.
^ The Barometric Pressure (BARO) is more than 75 kPa (10.8 psi).
^ The Vehicle Speed Sensor (VSS) is less than 120 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.

DIAGNOSTIC AIDS
The EVAP system tests run when the engine is first started and meets the Conditions for Running the DTC. 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 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 active.
6. This step verifies that repairs are complete and that no other condition is present.