DTC P0442 & P0455: EVAP System Leak Detected

NOTE: DTC P0442 and P1442 indicate a small leak, while P0455 and P1455 indicate a large leak in EVAP system.

NOTE: Performing this diagnostic test requires use of Kent-Moore EVAP system pressurizing equipment SST No. J41413, an ultrasonic leak detector and installation of a pressure service port at EVAP system purge valve (if not already equipped with one). Ultrasonic leak detector is susceptible to other shop noises and can give false indications of a leak. It is recommended that you try to eliminate any shop noises during this procedure to ensure accurate test results. Also, leak detector has difficulties hearing large leaks. Conduct a thorough visual inspection during diagnostics to ensure that no large leaks go undetected.

Connect Kent-Moore SST J41413 to EVAP system service port. See Figure. Ensure that fuel filler cap is tightly installed. Connect TECH 2 scan tool to Data Link Connector (DLC). Turn ignition on. Select ACTIVATE: SHUT-OFF VALVE. Following Kent-Moore instruction manual, pressurize EVAP system and test for leaks. If a leak is indicated, use ultrasonic leak detector to inspect all EVAP system components and hoses for leaks. Repair as necessary. Go to next step.
NOTE: It may be necessary to lower fuel tank to inspect components on top of tank.
Use scan tool to select ACTIVATE: EVAP DIAGNOSIS. If OK is indicated, fuel filler cap may have been left loose. Use scan tool to clear DTCs. If NOT READY is displayed, diagnosis has not yet been performed or has been cancelled. Roll vehicle forward or back, then use handbrake to stop. Reactivate EVAP DIAGNOSIS. If DTC P0442 or P0455 is displayed, recheck all EVAP components for leaks, including those installed at top of fuel tank.