Question about Cars & Trucks
Replaced gas cap
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.
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
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
Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.
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Posted on Feb 22, 2012
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Posted on Jan 02, 2017
P0420 is catalyst system efficiency below threshold (bank 1)
P0440 is evaporative emission control system malfunction
P0441 is evaporative emission control system incorrect purge flow
Posted on Mar 29, 2009
I would try to replace the gas cap first. If that doesn't solve it, you wll have to take it yor local repair shop and have them perform a smoke test. The technician can pinpoint your exact problem. I just fixed a 2003 Cavalier and it was a split gas tank. No other way to find that problem without the smoke.
Posted on Jun 08, 2009
SOURCE: 2003 monte carlo ss po440
you will need to drive about 50 miles till the computer checks the system since it was reset. Your check engine light may come back again, if it does run a vacum test..
Posted on Jul 23, 2009
SOURCE: I have a service engine light on
it can be in 2 spots it is usually under the truck by the fuel tank a black boxy shape mounted to frame the other spot is behind the throttle body
Posted on Oct 09, 2009
Testimonial: "Thank you,, this problem all started approx 2 weeks after I removed the throttle body for cleaning, this is where I will focus on"
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