Code P04000
 

2000 Galant ES 4 cyl
diagnostics reads "P0400 Exhaust Gas Recirculation Flow Malfunction". EGR valve definitely moves. Assuming the solenoid is the problem, how can I test this? I believe there are two solenoids. thanks

RE: Code P04000
 

hello! if you have a scanner you can go into the MFI section under vehicle tests and activate the solenoid. it should click. more than likely your EGR ports are clogged with carbon. the most effective way to clean out the ports is to remove the intake. then you have easy access. if you try on the car there isnt much you can get in the ports to clean out at that angle. what we do at our shop is remove the intake, totally strip it down. meaning remove all sensors and the throttle plate. send it to a machine shop and let them put it in there hot vat overnight. that always works!! be sure to wash it out very good when you get it back! that vat liquid doesnt burn very well and will make the SES light come on with a misfire code untill it all gets out of the intake!! good luck! greg....

RE: Code P04000
 

A way to check if the egr ports are clogged, hook up a vacuum pump to the egr valve and apply vacuum the car should try to stall at idle. If it doesn't change @ idle the egr ports are clogged.

RE: Code P04000
 

Simply pinch the vacuum line at the top of the throttle body (with the yellow tracer) and see what happens. If the engine stalls, the vacccum circuit and EGR ports are clear. What you need to do now is power the EGR solenoid with a 12v power supply and see if it's working. You can verify it's operation witha vacuum pump. Good luck.

JJ