Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0442: EVAP Leak Monitor Medium (.040") Leak Detected Or DTC P0455: EVAP Leak Monitor Large Leak Detected: Description
EVAP leak monitor is monitored immediately after a cold start, with ambient temperature 40-90°F (4.4-32.2°C) and engine coolant temperature within 10°F of ambient temperature. DTC P0442 will set in Powertrain Control Module (PCM) memory when PCM senses a leak of .040-.080" (.01-.02 mm) in Evaporative Emission (EVAP) system. DTC P0455 will set when PCM senses a leak bigger than .080" (.02 mm) in EVAP system. Possible causes for DTC to set are: leaking EVAP system component or intermittent Leak Detection Pump (LDP) monitor failure.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.