P0498EVAP System Vent Valve Control Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- The evaporative emission (EVAP) system stores fuel vapour from the tank in a charcoal canister; a purge valve lets the engine draw it off, and a vent valve opens the canister to fresh air. The vent valve is normally open and switched to ground by the module; P0449 (open), P0498 and P0499 form the newer code scheme for its circuit, used mainly by GM and Saab models with GM engines, while Ford uses P0446. P0498 means the control wire is shorted to ground: GM sees 0.5 Ω or less to ground with the driver off (20 of 25 samples), Saab below 2.6 V – MIL after two trips. The valve is then permanently energised and closed, so the tank is not vented and refuelling becomes difficult.
- What you may notice
- Check engine light on
- Refuelling difficult, nozzle clicks off
- Vacuum noise when opening the fuel cap
- Likely causes
- LikelyVent valve control wire chafed against ground (underbody, tank area)
- PossibleVent valve coil shorted internally
- PossibleCorrosion or water in the connector
- RareDriver in the engine module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €30 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.