P0498: EVAP Vent Valve Control Circuit Low
P0498 means the engine computer found the control wire of the EVAP vent valve shorted to ground, which keeps the valve closed. The car is usually drivable, but the check engine light stays on and filling the tank can become difficult.
You can drive, but get it checked soon
The car should run normally because limp mode is not expected with this code. The closed vent valve can make refueling difficult, and the fault keeps the car from passing an emissions test until it is fixed.
What it means
The evaporative emission (EVAP) system traps fuel vapor from the tank in a charcoal canister so it does not escape into the air. A purge valve lets the engine draw the vapor out, and a vent valve opens the canister to fresh air. The vent valve is normally open, and the engine module closes it by switching its control wire to ground. P0498 sets when that wire reads as shorted to ground even though the module is not driving it. The valve then stays energized and closed, so the tank cannot vent. This code is used mainly by GM and Saab models with GM engines. Ford uses P0446 for a related fault. The check engine light comes on after two trips, and the code needs a drive cycle (a set pattern of driving) to confirm a repair.
Likely causes
- Vent valve control wire chafed against ground (underbody, tank area)Very likely
The wire runs along the underbody near the tank, where rubbing against metal can wear through the insulation and short it to ground.
- Vent valve coil shorted internallyPossible
A shorted coil inside the valve pulls the circuit to ground and holds the valve closed.
- Corrosion or water in the connectorPossible
Moisture or corrosion at the plug can create a path to ground that the module reads as a short.
- Driver in the engine moduleLess likely
The switching circuit inside the module can fail, but this is the least common cause.
What you may notice
- Check engine light on
- Refueling is difficult and the pump nozzle clicks off
- Vacuum noise when opening the fuel cap
What to check, cheapest first
- 1Read the code and any related EVAP codes such as P0449 or P0499, then note the freeze-frame data. · you can do it
- 2Look at the vent valve connector near the tank or canister for water, corrosion, bent pins or a loose fit. · you can do it
- 3Inspect the vent valve wire along the underbody and around the tank for chafed insulation or spots touching metal. · you can do it
- 4Unplug the vent valve and clear the code. If the fault changes or the valve is stuck closed when powered, the valve itself is likely bad. · mechanic
- 5Measure the control wire's resistance to ground with the connector unplugged to find a short in the wiring. · mechanic
- 6If the valve and wiring are good, test the module driver, then clear the code and complete a drive cycle to confirm the repair. · mechanic
Related codes
Frequently asked questions
Can I drive with P0498?+
Usually yes, since limp mode is not expected. Expect a check engine light and possible trouble when refueling, so have it fixed soon.
Can a loose gas cap cause P0498?+
Not directly. P0498 is an electrical fault in the vent valve circuit. A loose cap is more associated with other EVAP leak codes.
Will P0498 pass an emissions test?+
Probably not. The code is emissions-relevant and keeps the check engine light on, so it should be repaired and the drive cycle completed first.
Is this an expensive repair?+
The repair is rated easy and can be done at home. The estimated time is about 0.3 to 1.5 hours, depending on whether it is the wiring, connector or valve.
Written with the help of AI from the public OBDex definition (CC0). Each make may use the code differently. Updated: 2026-11-10