DTC P0442: EVAP Leak Monitor Medium Leak Detected, DTC P0455: EVAP Leak Monitor Large Leak Detected Or DTC P0456: EVAP Leak Monitor Small Leak Detected: Testing

NOTE: Since a hot vehicle can conceal a leak, it is best to perform this test at room temperature. A loose gas cap may have caused this DTC to set. Ensure gas cap is tight and meets OEM specifications.

Turn the ignition on. With the DRBIII®, read DTCs. Is the Good Trip counter displayed and equal to zero? If yes, go to next step. If no, go to step 5.

WARNING: When performing test procedures, keep lighted cigarettes, sparks, flames and other ignition sources away from test area.

To continue testing you will need Miller Special Tool (8404) Evaporative Emission Leak Detector. The fuel tank should have between 20% and 80% of fuel tank capacity to properly test the EVAP system. Disconnect the vacuum supply hose at the Leak Detection Pump. Connect and apply a continuous vacuum supply (i.e. 20 in. Hg) to the Leak Detection Pump. A vacuum pump such as an A/C recovery unit works well. Using the DRBIII®, select Engine/System Tests and actuate the Leak Detect Pump Test (Option 3/Hold PSI). This energizes the LDP solenoid and allows the constant vacuum source to apply vacuum to the LDP pump diaphragm. This lifts the diaphragm up and seals the atmospheric canister vent valve at the bottom of the Leak Detection Pump. Connect the Red power lead of Miller Special Tool (8404) to the battery positive terminal and the Black ground lead to battery negative terminal. Connect shop air to the Evaporative Emission Leak Detector. Set the smoke/air control switch to AIR. Insert the tester's AIR supply tip (clear hose) into the appropriate calibration orifice on the tester's control panel (based on DTC leak size). Press the remote smoke/air start button. Position the Red flag on the air flow meter so it is aligned with the indicator ball. When the calibration is complete, release the remote button. The Evaporative Emission Leak Detector is now calibrated the flow meter in liters per minute to the size leak indicated by the DTC set in the PCM. Install the Service Port Adapter (8404-14) on the vehicle's service port. Connect the Air supply hose from the Evaporative Emission Leak Detector to the service port. Press the remote button to activate AIR flow. Larger volume fuel tanks, and/or those with less fuel, may require 4 to 5 minutes to fill. Compare the flow meter indicator ball reading to the red flag. ABOVE the Red flag indicates a leak present. BELOW the Red flag indicates a sealed system. Is the indicator ball above the Red flag? If yes, go to next step. If no, go to step 5.

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. The strong smell of fuel vapors may aid diagnosis also.

To continue testing, you will need Miller Special Tool (8404) Evaporative Emissions Leak Detector. Remove the Air supply hose from the service port. Connect the SMOKE supply tip (Black hose) to the service port. Set the smoke/air control switch to SMOKE. The flow meter indicator ball will not move at this point. Press the remote smoke/air start button. Ensure that smoke has filled the EVAP system by continuing to press the remote smoke/air start button, remove the vehicle fuel cap, and wait for the smoke to exit. Once smoke is indicated reinstall the fuel cap. For optimal performance, introduce smoke into the system for an additional 60 seconds; continue introducing smoke at 15 second intervals, as necessary. While still holding the remote smoke/air start button, use the White light (8404CLL) to follow the EVAP system path, and look for the source of the leak indicated by exiting smoke. If a leak is concealed from view (i.e., top of fuel tank), release the remote smoke/air start button, and use the Ultra Violet (UV) Black light (8404-UVL) and the Yellow Goggles (8404-20) to look for residual traces of dye that is left behind by the smoke. The exiting smoke deposits a residual fluid that is either bright Green or bright Yellow in color when viewed with a UV light. Was a leak found? If yes, repair or replace the leaking component as necessary. If no, go to next step.

NOTE: After disconnecting the EVAP Purge Solenoid vacuum connections, inspect the lines and solenoid for any signs of contamination from the EVAP Canister. This may indicate a faulty rollover valve. Rollover valve is located in top of fuel tank. Replace/repair as necessary.

Turn the ignition off. Disconnect the vacuum hoses at the EVAP Purge Solenoid. Using a hand vacuum pump, apply 10 in. Hg of vacuum to the EVAP Purge Solenoid vacuum source port on the component side. Monitor the vacuum gauge for at least 15 seconds. Does the EVAP Purge Solenoid hold vacuum? If yes, go to next step. If no, replace the EVAP Purge Solenoid.
At this time, the conditions required to set the DTC are not present. Use the Freeze Frame Data to help you duplicate the conditions that set the DTC. Pay particular attention to the DTC set conditions, such as, VSS, MAP, ECT, and Load. A thorough visual inspection of the EVAP system hoses, tubes, and connections may save time in your diagnosis. Look for any physical damage or signs of wetness at connections. The strong smell of fuel vapors may aid diagnosis also. Refer to any Technical Service Bulletins (TSB) that may apply. With the DRBIII® in System Tests, perform the LDP Monitor Test. This will force the PCM to run the LDP Monitor. If the monitor fails, further diagnosis is required to find faulty component. If the monitor passes, the condition is not present at this time. Were any problems found? If yes, repair as necessary. If no, test is complete.