DTC P0442: EVAP Leak Monitor Medium (.040") Leak Detected, DTC P0455: EVAP Leak Monitor Large Leak Detected Or DTC P0456: EVAP Leak Monitor Small Leak Detected: Testing
NOTE:
A loose fuel tank cap could cause this trouble code to set. Ensure fuel tank cap is tight and in good condition.
- Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is displayed and equal to zero, go to next step. If GOOD TRIP counter is not displayed and equal to zero, go to step 4
.CAUTION: When performing test procedures, keep lighted cigarettes, sparks, flames and other ignition sources away from test area.
- To test EVAP system properly, fuel tank should have 20-80 percent of fuel capacity. Miller Evaporative System Testing Kit (6872A) and Gas Cap Adapter (8382) are used to perform evaporative system pressure test. Connect scan tool to Data Link Connector (DLC). Connect EVAP system testing kit positive lead to positive battery terminal and negative lead to negative battery terminal. Using EVAP system testing kit, and instructions printed on EVAP system testing kit cover, perform EVAP system pressure pump self-test. Remove gas cap and install gas cap adapter to fuel tank. Install gas cap to gas cap adapter. Connect pressure supply hose from evaporative system testing kit to fitting on gas cap adapter. Disconnect vacuum supply hose at Leak Detection Pump (LDP). See Figure
. Apply a continuous vacuum supply of about 20 in. Hg to vacuum supply nipple on LDP. An A/C recovery unit works well for supplying a continuous vacuum supply. Turn ignition on. Using scan tool, select ENGINE SYSTEM TESTS, then LEAK DETECTION PUMP TEST. Read instructions on scan tool and then press ENTER. Select #3 HOLD PSI. Set EVAP system testing kit PRESSURE/HOLD valve to OPEN position and set VENT valve to CLOSED position. While monitoring EVAP system testing kit pressure gauge, turn EVAP system testing kit pump timer on. When pressure gauge reaches 14 in. H2O, turn PRESSURE HOLD valve to CLOSED position. Turn timer off. Note time and pressure. If pressure drops more than 6 in. H2O in 2 minutes, go to next step. If pressure drops 6 in. H2O or less in 2 minutes, go to step 4
.NOTE: A thorough visual inspection of EVAP system hoses, tubes and connections may save diagnostic time. Look for any physical damage or signs of wetness at connections.
- EVAP system pressure pump self-test should still be running. If scan tool has timed out, restart EVAP system pressure pump self-test. Set EVAP system testing kit PRESSURE/HOLD valve to OPEN position. Set VENT valve to CLOSED position. Turn EVAP system testing kit pump timer on. To prevent noise from interfering with test, move EVAP system kit pressure gauge away from vehicle. Using Ultrasonic Leak Detector (6904A), check for leaks at all EVAP system hoses and connections. Repair or replace leaking component(s) as necessary. If no leaks exist, no problem is indicated at this time. Test is complete.
- At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Using scan tool, review FREEZE FRAME data. Attempt to duplicate condition that caused DTC to set. Thoroughly perform a visual inspection of EVAP system hoses, tubes and connections. Look for any physical damage or signs of wetness at connections. Visually inspect related connectors and wiring harness for damage. Check for any related technical service bulletins that may apply. Turn ignition on. Using scan tool in SYSTEM TESTS, perform LDP monitor test. This will force the PCM to run LDP monitor. If monitor fails, further diagnosis is required to find faulty component. If monitor passes, no problem is indicated at this time. Test is complete.