P0498
EVAP System Vent Valve Control Circuit Low
The vent valve closes the EVAP canister to atmosphere during leak tests. The control line for that valve is shorted to ground - the ECU drives the valve and measures voltage below the expected level, indicating either a harness short or an internal solenoid short.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Common causes
Ordered by how often each turns out to be the cause.
- Control line shorted to groundCommon
- Vent solenoid internally shortedPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- EVAP Vent Valve
- EVAP Vent Wiring
P0498 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.