P0442

Evaporative Emission System Leak Detected (Small Leak)

🟢 MONITOR — NOT URGENT POWERTRAIN · EVAP System

EVAP monitor detected a leak approximately 0.020" or smaller in the fuel vapor system.

What You'll Notice
  • MIL on, no drivability symptoms
  • Faint gasoline smell near fuel cap area (rare)
Probable Causes
  • Gas cap not tightened properly after fill-up — check here first, free fix
  • Cracked or deteriorated gas cap seal
  • Purge valve or vent valve leaking internally
  • Cracked EVAP charcoal canister hose or canister itself
Direct Repair Steps
  1. Remove and reinstall gas cap firmly until it clicks; clear code, drive, recheck
  2. Replace gas cap ($8–25) if code returns — most common definitive fix
  3. Smoke-test EVAP system from service port to locate leak if cap replacement fails
  4. Replace faulty purge solenoid or vent valve if leak is localized there
Vehicles Affected
chevy ford honda toyota jeep bmw subaru
BlueDriver OBD2 scanner
RECOMMENDED SCANNER
BlueDriver Bluetooth Pro OBDII Scanner
Reads P0442 and 5,000+ codes. Live data, enhanced diagnostics, repair reports. Works on all 1996+ vehicles.
View on Amazon →

Best next step

If you still need the scanner, compare options first so you buy the right tool once. If you already know the make, go straight to the brand-specific page for Chevy.

Compare scanners Open Chevy guide

Best Scanner Pick for P0442 Workflows

Fast root-cause diagnosis

BlueDriver Bluetooth Pro

Guided reports and easier interpretation for most DIY users.

Check Price
Advanced troubleshooting

OBDLink MX+

Higher data refresh speed for deeper live-data analysis.

Check Price

Quick answers

What does P0442 mean?
EVAP monitor detected a leak approximately 0.020" or smaller in the fuel vapor system.
Is P0442 serious?
It depends on the system and symptoms, but the page ranks the severity and likely causes so you can decide whether to stop driving or continue with caution.
What should I buy before troubleshooting P0442?
A reliable OBD2 scanner helps confirm the code, read live data, and avoid guessing before repairs.

Related Codes

Best Scanner Guides Related to P0442

Related Symptom Clusters

Best Scanner by Affected Make