P0497
EVAP System Low Purge Flow
The evaporative emissions system measures purge flow either via a dedicated purge flow sensor or via short-term fuel trim response when the purge valve opens. The flow is significantly lower than expected for the commanded purge rate - typically a clogged purge line, a stuck purge valve, or a leaking vapor canister vent.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
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.
- Purge valve sticking partially closedCommon
- Purge line restricted by debris or kinksPossible
Parts involved
- EVAP Purge Valve
- EVAP Purge Line
- Vapor Canister
P0497 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.