P0498 - EVAPORATIVE EMISSION SYSTEM VENT VALVE CONTROL CIRCUIT LOW

The Evaporative Emissions Control System (EVAP) is designed to capture fuel vapors and send them to the engine, where they can be burned. This system has an activated carbon canister where the vapors are stored, a pipe that connects the canister to the fuel tank, and an engine inlet. Two valves control the storage and flow of the vapors.

Monitoring and controlling the EVAP system is the Engine Control Module (ECM). If the ECM finds a malfunction in the vent valve circuit, it will set the diagnostic code P0498 OBDII.

• Check Engine light illuminated.
• Engine loses performance.
• The fuel economy is decreased.

DTC P0498 OBD2 code is set when one or more of the following occurs:

• The vent valve may be defective.
• The circuit wiring may be faulty.
• Vessel shutoff valve harness open or short-circuited.
• Canister closed valve circuit bad electrical connection.
• Faulty Engine Control Module (ECM).

When troubleshooting problems that are related to the P0498 OBDII fault code you should do the following things:

• Check the fuses that drive the ventilation solenoid. If one of these is in bad condition you should replace them.
• Check the condition of the wires. And check that they are not rubbing against other components. Repair or replace as necessary.
• Visually inspect the vent valve. It may have cracks or other damage.
• Make sure the wires to and from the ECM have continuity.
• Use a DVOM to check the resistance of the vent. You should get a low resistance. Compare to the manufacturer's specifications and if the reading obtained is not within those specifications, replace the vent valve.