Is it safe to drive with a P0442 code?

Severity is low. Address P0442 sooner rather than later — driving with an active check engine light can worsen the problem or void emissions warranties.

How much does it cost to fix P0442?

Repair costs for P0442 typically range from $0 to $300 in the US, depending on the underlying cause. The most common fix is: Loose or worn gas cap.

What are the symptoms of P0442?

Check engine light. No drivability issues.

Check Engine Code

P0442

Evaporative Emission Control System Leak Detected (Small Leak)

Severity: low DIY difficulty: 1/5 Typical cost: $0–$300

Last updated April 30, 2026

What P0442 means

The ECM pressurizes the EVAP system and watches for a drop. P0442 = a small leak — the size of a pinhole. This is the classic 'check your gas cap' code: ~30% of the time a cap fix clears it.

Symptoms

Check engine light
No drivability issues

Likely causes (most common first)

Loose or worn gas cap
Cracked EVAP hose or line
Failed purge valve or vent valve
Damaged charcoal canister
Small crack in the filler neck

Can I keep driving?

Low — mostly emissions/economy

Typical repair cost

DIY fixes can start near $0 (parts only). Shop repairs for P0442 typically run up to $300 depending on the underlying cause and vehicle. Start with the most common cause — Loose or worn gas cap — before throwing parts at it.