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P0456 - EVAP Control System Leak Detected (Very Small Leak)
This code is for a small leak the PCM (Engine Computer) has detected in the fuel vapor system between the fuel tank and the engine. Not a vacuum leak.
I just need to know if the AC has to be on when it stalls when stopping?
The engine stalls with a/c on or off when stopping.
Make sure all the hoses are connected to the air intake box and tube. Make sure the air filter box is properly and completely closed.
All air ducts and hoses are connected
Does the tool you used to get the trouble code also monitor the sensors from the PCM (Engine Computer)?
Yes, I am using a snapon midos
See if you can monitor the Long fuel trims and the short fuel trims for the engine while it is running.
Ok, unplug the VMV (Vapor Management Valve) electrical connector and drive the vehicle and see if the stalling problem is still present. We have seen the VMV stick open and flood the engine with fuel vapors from the fuel tank.
I unplugged electrical connector at valve. I also plugged off the small vaccum line to valve and I plugged off nipple on plenum where the large line connects.. The engine still stalls.
Ok. With the scan tool attached watching the SHRTFT for both banks. Start the engine and slowly spray carb cleaner or brake cleaner around the intake manifold and see if the fuel trims change.
There is no change in fuel trim.
Have you actually tested the actual fuel pressure with a manual fuel pressure gauge connected to the vehicle?
I checked fuel pressure it is 30 to 40 psi. 30 at idle and go to 40 when accelerated
Disconnect the line from the VMV from the manifold and watch the fuel trim. If the valve is sticking open, the vacuum line disconnected will not effect the operation of the valve and it will still allow fuel vapors into the engine.