Hello,

I have a 2001 Montero XLS. Has just 64000 miles on it.
I have replaced the EGR Solenoid and the EGR valve.
Still I get the P0400 code. I checked all the vacuum hoses going to and from the EGR & Solenoid Valves. They all look ok. There is exhaust gas coming in via the EGR valve as it gets hot when applied a vacuum externally.

Is the EGR solenoid valve generally open? Since I disconnected it and sucked air and it was allowing free flow of air.

What should I do where should I look further?

Please help.

 

When i got this code on my montero...i checked all vacuum hoses and the egr solenoid...they say the egr valve itself rarely breaks down,tested it and it sure works. Changed the egr solenoid because its not working as it should. I also cleaned the intake manifold itself concentrating on the ports where the vacuum hoses attaches to. There was some sort of restriction on one of those ports...everything worked fine for a few months....then the code came back....egr solenoid again...my mistake since I bought a cheap one the first time..
Some say the aftermarket egr solenoid breaks down a lot compared to the original brand...but after using the aftermarket one that I got from autozone...still works fine.

 

EGR solenoid on these vacuum EGR valves turns on and of many times per second. This way ECU can regulate how much gas is being recirculated. If you have not yet done so, replace the ERG solenoid. Then, if EGR code comes back, I's suggest you carefully check your connectors and wire harness (clean and repair if needed). It is possible that the EGR solenoid is getting an intermittent signal and that triggers EGR code. One other thing to check is the MAP sensor on top of the intake manifold. Take it off and make sure the little pinhole on it is clear as is the hole in the intake manifold through which it measures the pressure. If ether one of them is plugged the ECU will be not be able to "confirm" via feedback that the signal sent to EGR solenoid was executed.
It sounds like you already checked vacuum hoses and EGR pipe. Those are often first line culprits.