2004 Dodge Neon emission code

  • 2004 DODGE NEON
  • 4 CYL
  • FWD
  • 75,000 MILES
Im having a problem finding the exact cause of a small leak causing a check engine light. The code is p0440 small evap leak but cannot find a leak in system was weondering if anyone else has the same problem or knows maybe what it could be
Do you
have the same problem?
Monday, January 5th, 2009 AT 7:38 PM

1 Reply

P0440 OBD-II Trouble Code Technical Description: Evaporative Emission Control System Malfunction
What does that mean?

This indicates that a part of the EVAP control system is no longer fuctioning correctly. The EVAP system consists of many parts, including (but not limited to) the gas cap, fuel lines, carbon canister, purge valve, and other hoses. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.


You likely won't notice any drivability problems.


A code P0440 could mean one or more of the following has happened:

* The gas cap is not installed or working properly
* The purge solenoid has failed
* The canister is plugged and not working properly

Possible Solutions

With a P0440 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try:

* Remove and reinstall the gas cap, clear the code, and drive for a day and see if the codes come back.
* Inspect the EVAP system for cuts/holes in tubes/hoses
* Inspect for damaged or disconnected hoses around the Evap purge solenoid
* Check and/or replace the sensor
* Check and/or replace the purge valve
* Have a professional use a smoke machine to detect leaks


Was this
Tuesday, January 6th, 2009 AT 1:23 AM

Please login or register to post a reply.

Recommended Guides