P0440 Evaporative Emission Control System Malfunction

Description and meaning of DTC p0440

This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. Although generic, the specific repair steps may vary depending on make/model. This indicates that a part of the EVAPcontrol system is no longer fuctioning correctly. The EVAP system consistsof many parts, including (but not limited to) the gas cap, fuel lines, carboncanister, purge valve, and other hosesThe (EVAP) emissioncontrol system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routedby hosesto a charcoal canister for storage. Later, when the engine is running a purgecontrol valve opens allowing intake vacuum to siphon the fuel vapors intotheengine.

p0440 diagnostic trouble code symptoms

You likely won't notice any drivability problems.

DTC p0440 - possible causes

A code P0440 could mean one or more of the following has happened:The gas cap is not installed or working properlyThe purge solenoid has failedThe canister is plugged and not working properly

How to fix OBD-II diagnostic trouble code p0440

With a P0440 OBD-II trouble code, diagnosis can be tricky at times. Hereare some things to try:Remove and reinstall the gas cap, clear the code, and drive for a day andsee if the codes come back. Inspect the EVAP system for cuts/holes in tubes/hosesInspect for damaged or disconnected hoses around the Evap purge solenoidCheck and/or replace the sensorCheck and/or replace the purge valveHave a professional use a smoke machine to detect leaks

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