Diagnostic Instructions

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

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Ignition 1 Voltage	P0498	P0498	--	--
EVAP Canister Vent Solenoid Valve Control Circuit	P0498	P0498	P0499	--

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

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

Conditions for Clearing the DTC

DTC P0498 and P0499 are Type A DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Description and Operation

Evaporative Emission Control System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Circuit/System Verification

1. With a scan tool, command the EVAP Vent Solenoid ON and OFF. You should feel or hear an audible click as the solenoid is commanded ON and OFF.
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 Data List.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector of the EVAP vent solenoid valve .
2. Ignition ON, verify a test lamp illuminates between the ignition 1 voltage circuit and ground.

⇒	If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition 1 voltage circuit fuse is open, test all components connected to the ignition 1 voltage circuit and replace as necessary.

3. Ignition OFF, connect a test lamp between the control circuit and the ignition 1 voltage circuit.
4. Ignition ON, command the EVAP vent solenoid valve ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	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.

5. If all circuits/connections test normal, test or replace the EVAP vent solenoid valve.

Component Testing

1. Measure for 18-28 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.

Control Module References for engine control module replacement, setup, and programming