P0496Powertrain
Powertrain · SAE
EVAP System — Excessive Purge Flow
Meaning
The ECU detects EVAP vapour flow when the system should be closed (non-purge condition). Usually the purge valve stays open or leaks, letting unplanned vapours into the intake.
Common causes
- Purge valve stuck open or leaking
- Faulty vent valve
- Disconnected or damaged EVAP hoses
- Saturated charcoal canister
- Electrical fault at the purge solenoid
Symptoms
- Check engine light on
- Rough idle, especially after refuelling
- Hard starting with a full tank
- Slightly increased fuel consumption
Severity
Mild/moderate: uncontrolled evaporative emissions; rarely strands the car but should be fixed for inspection and efficiency.
What to do
- Command the purge valve with the scan tool and check it seals
- Inspect EVAP hoses, vent valve and charcoal canister
- Run an EVAP leak/vacuum test
- Replace the purge valve if it stays open or leaks