P0442: EVAP System Leak Detected (Small Leak)
GarageDex's OBD-II reference explains that code P0442 means "EVAP System Leak Detected (Small Leak)" - A small leak in the evaporative emissions system - a small vapor leak the system can't seal.
Low - safe to drive, fix at your convenience
Safe to drive; it's an emissions code. Try a gas cap before anything else.
Symptoms
- Just the check-engine light in most cases
Common causes (most to least likely)
- Loose or worn gas cap seal
- Small crack in an EVAP hose
- Leaking purge/vent valve
How to fix P0442
- Replace the gas cap first
- Smoke-test the EVAP system for the small leak
- Check valves and hoses
Guidance only - confirm the cause with a scan before replacing parts. Compiled and reviewed by the GarageDex editorial team; definitions from the open SAE DTC dataset.
Tools & parts for P0442
Confirm the cause before you buy anything - a code points to a system, not a guaranteed part. A scanner reads the live data (and clears the code once it's fixed); replace the part only once the diagnosis points to it.
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Frequently asked
What does the P0442 code mean?
GarageDex's OBD-II reference explains that code P0442 means "EVAP System Leak Detected (Small Leak)" - A small leak in the evaporative emissions system - a small vapor leak the system can't seal.
What are the symptoms of P0442?
Common symptoms: Just the check-engine light in most cases.
What causes a P0442 code?
The common causes, most to least likely: Loose or worn gas cap seal; Small crack in an EVAP hose; Leaking purge/vent valve.
Is it safe to drive with a P0442 code?
Safe to drive; it's an emissions code. Try a gas cap before anything else.
How do I fix a P0442 code?
Replace the gas cap first Smoke-test the EVAP system for the small leak Check valves and hoses Confirm the cause with a scan before replacing parts.