DTC P0442: EVAP System Medium Leak Or DTC P0455: EVAP System Large Leak: Testing
CAUTION:
When performing test procedures, keep lighted cigarettes, sparks, flames and other ignition sources away from test area.
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® scan tool, read DTCs and record the related freeze frame data. Is the Good Trip counter displayed and equal to zero? If yes, go to next step. If no, go to step 7.
- Perform a visual and physical inspection of the entire evaporative emission system. Check for the follow conditions; holes or cracks, loose seal points, evidence of damaged components, incorrect routing of hoses and tubes, fuel cap gasket seal. Were any of the above conditions found? If yes, repair as necessary. If no, go to next step.
- To continue testing you will need Miller Tool (8404) Evaporative Emission Leak Detector (EELD). The fuel tank should have between 20-80 percent of fuel tank capacity to properly test the EVAP system. Connect the Red power lead of the EELD to the battery positive terminal and the Black ground lead to battery negative terminal. Block the vent hose of the EVAP canister. Connect shop air to the EELD Set the SMOKE/AIR control switch to AIR. Insert the testers AIR supply tip (clear hose) into the appropriate calibration orifice on the testers 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 EELD 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 vehicles service port. Connect the AIR supply hose from the EELD to the service port. Press the remote button to activate AIR flow. Larger volume fuel tanks, lower fuel levels or if the vehicle is equipped with a flow management valve may indicate high flow and will require 4-5 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 7.
- 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. To continue testing, you will need Miller Tool (8404) Evaporative Emissions Leak Detector (EELD). 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 in the smoke mode. 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 (8404-CLL) 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 Ultraviolet (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. Carefully inspect the vent side of the EVAP canister. Due to the filtering system in the canister the smoke may not be as thick. Introducing smoke into the filtered side of the canister may assist in locating the leak. Was a leak found? If yes, repair or replace the leaking component as necessary. If no, go to next step.
- 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. 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 to the "CAN" of the EVAP purge solenoid. 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.
- The fuel level must be below 85 percent, or the ORVR control valve will seal the tank. Turn the ignition off. Install the Miller Gas Cap Adapter (8382). Attach the gas cap to the adapter. Connect a hand-held vacuum pump to the gas cap adapter. At 1 in. Hg the NVLD switch should close. Using a Miller Manometer (6872A) connected to the service port can aid in properly reading the system vacuum. Slowly apply vacuum while monitoring the NVLD switch state on the DRBIII® scan tool. Do not exceed 2 in. Hg while performing this step. The NVLD switch reads normally open. When the vacuum is applied and 1 in. Hg is reached the switch state should be in the closed position. Once the vacuum has been released the switch state should return to the open position. Did the NVLD Switch operate as described above? If yes, go to next step. If no, replace the NVLD assembly.
- Review the DRBIII® scan tool scan tool freeze frame information. If possible, try to duplicate the conditions under which the DTC was set. Refer to any Technical Service Bulletins (TSB) that may apply. A loose gas cap could have caused this DTC to set. Make sure gas cap is tight and in good condition. Ensure the gas cap meets OEM specifications. Perform a visual and physical inspection of the entire evaporative emission system. Check for the following conditions; holes or cracks, loose seal points, evidence of damaged components, incorrect routing of hoses and tubes, fuel cap gasket seal. Were any of the above conditions found? If yes, repair as necessary. If no, test complete.
WARNING:
Keep lighted cigarettes, sparks, flames, and other ignition sources away from the test area to prevent the ignition of explosive gases. Keep the test area well ventilated.
WARNING:
When the engine is operating, do not stand in a direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing.