P0442 Evaporative Emission Control System Leak Detected (small leak)

Description and meaning of DTC p0442

This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to many OBD-II equipped vehicles. Although generic, the specific repair steps may vary depending on make/model. This code is found on many makes including but not limited to Ford, GMC, Jeep, Dodage, Toyota, BMW, Chrysler, Subaru, etc. The vehicle's PCM (powertrain control module) tests the evaporative emissions (EVAP) system for large and small leaks among other conditions. In the case of this DTC, it indicates a fuel vapor leak in the EVAP control system. It means a verysmall leak has been detected. In fact, the leak can be from a hole as smallas 0. 04 in diameter. The (EVAP) emission control system prevents the escapeof fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hosesto a charcoal canister for storage. Later, when the engine is running a purgecontrol valve opens allowing intake vacuum to siphon the fuel vapors into theengine to be burned. That results in decreased vehicle emissions.

p0442 diagnostic trouble code symptoms

The only thing you will notice is the Malfunction Indicator Lamp (MIL) a. k. a. Check Engine Light will be illuminated. You likely won't notice any drivability problems although sometimes a fuel odor may be noticed.

DTC p0442 - possible causes

A code P0442 most likely means one or more of the following has happened:A loose or improperly affixed gas capA non-conforming gas cap (i. e. not factory/original brand)A small leak/hole in a fuel vapor hose/tubeOther small leak in EVAP systemFaulty vent o-ring sealDefective vent valveDefective purge valveDefective leak detection pump

How to fix OBD-II diagnostic trouble code p0442

With a P0442, the most common DIY repair is to:Remove and reinstall the gas cap, clear the codes, and drive for a day andsee if the codes come back. Otherwise, replace the gas cap (we recommend an OEM original part, not aftermarket part), orVisually inspect the EVAP system for cuts/holes in tubes/hosesMore advanced troubleshooting steps include:Using an advanced scan tool, perform an EVAP leak testVerify operation of the EVAP purge solenoid / valvePerform a smoke test to see where the leak isGenerally there are vehicle and model specific procedures for proper diagnosis of this DTC. Other EVAP DTCs: P0440 - P0441 -P0443 - P0444 - P0445 - P0446 - P0447 - P0448 - P0449 - P0452 - P0453 - P0455 - P0456

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