Diagnostic trouble code

P0442 EVAP System Small Leak Detected

The EVAP monitor detects a small leak in the fuel-vapor system.

EVAP Leak & Purge Codes

Read This First

This code identifies the failed diagnostic test or circuit family. Confirm the basic checks before replacing parts, and keep freeze-frame data until the repair is verified.

Common Checks

  • Check the fuel cap or capless filler seal.
  • Inspect EVAP hoses, purge valve, vent valve, and canister for cracks or loose connections.
  • Smoke-test the EVAP system if visual checks do not find the leak.

Common Repairs

  • Tighten or replace a damaged fuel cap where equipped.
  • Clean or repair a capless filler seal.
  • Replace cracked EVAP hoses or a leaking purge/vent valve.

Mustang Notes

Model-Year Applicability

Listed for 1996 and newer traditional gasoline Mustang pages in this first-pass catalog. Engine, calibration, and Ford-specific codes may narrow that range as more service data is added.

Sources

  1. SAE J2012DA Digital Annex of Diagnostic Trouble Code Definitions