Urgency: Low
Loose Gas Cap Light
This is usually informational. Address it at your convenience.
What the Loose Gas Cap Light Means
The loose gas cap light on a your car warns that the fuel filler cap is not sealed, which lets the evaporative emissions (EVAP) system detect a leak. It is a cheap, easy fix but can otherwise trigger the check engine light.
Common Causes
- Cap not tightened after fuelling
- Worn or cracked cap seal
- Damaged filler neck
- Faulty EVAP purge/vent valve
How to Fix It
- Remove and refit the fuel cap until it clicks
- Inspect the cap seal for cracks or debris
- Replace a worn cap (inexpensive)
- Drive several cycles for the light to clear
- Scan for EVAP codes (P0442/P0455) if it persists
Related DTC Codes
| Code | Meaning |
|---|---|
P0442 | EVAP System Leak Detected (Small Leak) A small evaporative emissions leak, very often a loose or worn fuel filler cap. |
P0455 | EVAP System Leak Detected (Large Leak) A large evaporative emissions leak, typically a missing gas cap or a cracked EVAP hose. |