DTC P0440: General EVAP System Failure: Testing

If any of the following DTCs are set (DTC P0443, DTC P0452, DTC P0453, DTC P0498 or DTC P0499) diagnose them first before continuing with P0440, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . Ignition on, engine not running. 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, see INTERMITTENT CONDITION under SELF-DIAGNOSTIC SYSTEM.
Perform a visual and physical inspection of the entire evaporative emission system. Check for the following conditions; hoses disconnected or left off, holes or cracks, loose seal points, evidence of damaged components, incorrect routing of hoses and tubes, fuel cap left off or bad gasket seal. Were any of the conditions found? If yes, repair as necessary. If no, go to next step.
Turn the ignition off. Carefully inspect the EVAP purge solenoid vacuum supply hose for proper routing. Check for a pinched or plugged hose from the throttle body to the purge solenoid. Ensure the vacuum port at the throttle body is free from any blockage. Were any problems found? If yes, repair or replace the vacuum supply, hose/tube as necessary. If no, go to next step.
Disconnect the vacuum supply hoses form the EVAP purge solenoid. Using a hand vacuum pump, apply 10 in. Hg to the "CAN" side of the EVAP purge solenoid. Ignition on, engine not running. Observe the vacuum gauge. With the DRBIII® scan tool, actuate the EVAP purge solenoid. Does the vacuum drop when the solenoid is actuated? If yes, go to next step. If no, replace the EVAP purge solenoid.
The fuel level must be below 85 percent, or the Onboard Refueling Vapor Recovery (ORVR) system 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. Note, at 1 in. Hg the 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, see INTERMITTENT CONDITION under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.

WARNING: Keep lit 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.

NOTE: The fuel tank should have between 20-80 percent of fuel tank capacity to properly test the EVAP system.

To continue testing you will need Miller Tool (8404) Evaporative Emission Leak Detector (EELD). Connect the Red power lead of EELD to the battery positive terminal and the Black ground lead to battery negative terminal. See charts and graph support material EELD calibration setup for, an example. 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 0.040" orifice on the testers control panel. 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. 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, this 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 8.
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 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 (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 are 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 or dye may or may not be visual. 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, before continuing disconnect the PCM harness connector and check the related wiring terminals for corrosion, damage or terminal push out. Repair as necessary. Pay particular attention to all power and ground circuits. If there are no possible causes remaining, replace and program the PCM. See PROGRAMMING .
Turn the ignition off. Disconnect the NVLD electrical harness connector. Check connectors, clean/repair as necessary. Using a jumper wire, jumper across the (K107) NVLD switch sense circuit and the (Z1) ground circuit in the NVLD electrical harness connector. Monitor the NVLD switch state on the DRBIII® scan tool. Does the switch change from OPEN to CLOSED. If yes, replace the NVLD assembly. If no, go to next step.
Turn the ignition off. Disconnect the NVLD electrical harness connector. Measure the resistance between the (Z1) ground circuit and ground. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the open in the (Z1) ground circuit.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool (8815) to perform diagnosis.

Turn the ignition off. Disconnect the NVLD electrical harness connector. Disconnect the PCM harness connectors. Measure the resistance of the (K107) NVLD switch signal circuit from the NVLD electrical harness connector to the appropriate terminal of the Miller Special Tool (8815). Is the resistance below 5.0 ohms? If yes, before continuing disconnect the PCM harness connector and check the related wiring terminals for corrosion, damage or terminal push out. Repair as necessary. Pay particular attention to all power and ground circuits. If there are no possible causes remaining, replace and program the PCM. See PROGRAMMING . If no, repair the open in the (K107) NVLD switch signal circuit.