P0498

DTC P0498

DTC DESCRIPTORS

DTC P0498
Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit Open

DTC P0499
Evaporative Emission (EVAP) Vent Solenoid Valve Control Circuit Shorted

DIAGNOSTIC FAULT INFORMATION




Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
The evaporative emission (EVAP) vent solenoid valve is used for EVAP system diagnostics. The EVAP vent solenoid valve is a normally open valve. Ignition voltage is supplied directly to the EVAP vent solenoid valve. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

CONDITIONS FOR RUNNING THE DTC
- The ignition is ON or the engine is operating.
- The DTCs runs continuously once the above conditions are met.

CONDITIONS FOR SETTING THE DTC

P0498
The ECM detects the EVAP vent solenoid valve control circuit is open.

P0499
The ECM detects the EVAP vent solenoid valve control circuit is shorted to ground or voltage.

ACTION TAKEN WHEN THE DTC SETS
DTC P0498 and P0499 are Type B DTCs.

CONDITIONS FOR CLEARING THE DTC
DTC P0498 and P0499 are Type B DTCs.

CIRCUIT/SYSTEM VERIFICATION
1. Start the engine, observe the DTC information with a scan tool. DTCs P0016 and P0340 should not set.
2. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

CIRCUIT/SYSTEM TESTING
1. Ignition OFF, disconnect the harness connector of the EVAP vent solenoid valve.
2. Connect a test lamp between the ignition 1 voltage circuit of the EVAP vent solenoid valve and the negative terminal of the battery.

IMPORTANT: The test lamp is used to load the circuit and may not illuminate.

3. Ignition ON, test for less than 0.1 volt between the ignition 1 voltage circuit of the EVAP vent solenoid valve and the positive terminal of the battery.
- If greater than 0.1 volt, repair the ignition 1 voltage circuit of the EVAP vent solenoid valve for a short to ground or an open/high resistance.
4. With the ignition OFF, connect a test lamp between the control circuit and the ignition 1 voltage circuit of the EVAP vent solenoid valve.
5. With the ignition ON, use a scan tool to command the EVAP vent solenoid valve ON. The test lamp should pulse ON and OFF for about 3-5 seconds.
- If the test lamp remains ON all the time, test for a short to ground on the control circuit. If circuit/connections test normal, replace the ECM.
- If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM.
6. If all circuits/connections test normal, test or replace the EVAP vent solenoid valve.

COMPONENT TESTING
1. Measure for 24-28 ohms of resistance between the terminals of the EVAP vent solenoid valve.
- If the resistance is not within the specified range, replace the EVAP vent solenoid valve.
2. Test for infinite resistance between each terminal of the EVAP vent solenoid valve and the EVAP vent solenoid valve housing.
- If less than infinite resistance, replace the EVAP vent solenoid valve.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests