How do I fix fault code P0498 on a Chevrolet Corvette C7?

Difficulty: Moderate (Requires lifting the vehicle, removing wheel well liners, and basic electrical diagnosis)

Fault code P0498 indicates an Evaporative Emission System Vent Valve Control Circuit Low. On these circuit codes, a "low" condition generally means you have a short to ground or high resistance on either the 12V power side or the control (ground) side of the circuit ¹.

On the C7, the EVAP vent valve is a normally-open solenoid located in the right rear (passenger side) wheel well ². The valve receives constant 12V power from a fuse, and the ECM supplies the ground to close the valve when it runs an EVAP system monitor test.

Here is the procedure to track down the fault and fix it:

1. Check the Fuse

Before you start tearing the car apart, check the fuse that supplies 12V power to the EVAP vent solenoid. If the fuse is blown, it's a dead giveaway that you have a short to ground on the power side of the circuit ¹. I don't have the exact fuse number for your C7 in front of me, so check your owner's manual or the fuse box diagram for the EVAP emissions fuse.

2. Access the Vent Valve and Inspect Wiring

If the fuse is good, you need to get eyes on the valve itself.

• Safely support the rear of the car on jack stands and remove the right rear wheel.
• Remove the right rear wheel well liner to access the EVAP canister and vent valve ².
• Visually inspect the wiring harness and the connector going to the valve. Look for pinched wires, chafing against the chassis, or rodent damage—which is a known issue for EVAP wiring in this location on the C7 ⁶.

3. Test the Circuit

If the wiring looks physically intact, you'll need a digital multimeter (DVOM) and ideally a bi-directional scan tool to properly diagnose the circuit.

• Disconnect the plug at the vent valve and verify you have 12V on the power wire with the ignition on.
• The community highly recommends performing dynamic voltage drop testing on the circuit rather than just static resistance (ohm) testing, as static testing can miss high-resistance faults ¹.
• If you have a bi-directional scanner, command the EVAP vent valve closed and verify the ECM is successfully providing the ground signal.

4. Replace the Valve (or Module)

If your wiring, power, and ground all test completely fine, the vent valve itself likely has an internal short and needs to be replaced.

Clear the codes and take the car for a road test to run the EVAP monitor. In rare cases, if the wiring is good and a new valve doesn't clear the P0498, the fault may lie upstream in the Fuel Level Sensor Control Module ¹. However, a failed valve or damaged wiring in the wheel well is far more common.