Evaporative emission (EVAP)
P0442 — Evaporative Emission System Leak Detected (Small Leak)
The ECU ran a leak test on the EVAP system and found a small leak, roughly the size of a 1 mm hole. It is one of the most common reasons for a check engine light.
Common causes
- Loose, worn or incorrect fuel cap
- Small crack in an EVAP hose or fitting
- Leaking purge or vent valve
- Cracked filler neck or tank seal
- Leak in the charcoal canister
Symptoms
- Check engine light
- Slight fuel smell
- Failed emissions test
- No driving symptoms in most cases
How to check
- Tighten the fuel cap or replace it if the rubber seal is cracked, then clear the code and drive for the monitor to rerun
- Inspect hoses, connectors and valves
- Use a smoke machine to find the leak
- Test the purge and vent valves
Can you keep driving?
Safe to drive. It affects emissions only; repair at your convenience.
Related codes
Frequently asked questions
- What does P0442 mean?
- The EVAP system has a small leak that the ECU's pressure test detected.
- Can a loose gas cap cause P0442?
- Yes, it is one of the most common causes.
General reference information. It does not replace a diagnosis on your own vehicle. The same code can have different causes depending on make, model year and engine; check the manufacturer's documentation or ask a technician with a scan tool.