The evaporative-emissions system detected a small leak. On the 987 the overwhelmingly common cause is a loose or worn fuel-filler cap; other causes are cracked EVAP hoses or a leaking purge/vent valve. No drivability effect but it will keep the CEL on.
SYMPTOMS
- Check-engine light
- Possible faint fuel smell
- No drivability effect
LIKELY CAUSES
- Loose, worn or wrong fuel-filler cap (most common)
- Cracked or disconnected EVAP hose
- Leaking purge or vent valve
- Faulty charcoal canister
DIAGNOSIS STEPS
- Inspect and reseat/replace the fuel cap first
- Smoke-test the EVAP system to locate the leak
- Check purge and vent valve operation
- Clear the code and confirm it stays off
RELATED PARTS
- Fuel filler cap
- EVAP purge valve
- EVAP hoses