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Ron, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 35614
Experience:  35 years in the AUtomotive repair Business
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PO401 code. EGR valve opens up completely with a hand pump,

Customer Question

PO401 code. EGR valve opens up completely with a hand pump, motor starts to run rough when I do that. next I check the suction from the manifold , it reads at 20inches of vacum, then I measured after the solinoid, and it still reads the same. Then I disconnect the electrical plug from solinoid, measure the vacum, still 20 inches. of course I measured at 2500rpm. anyway I removed the solinoid and checked the resistance on it , it was 31.7ohms. then I tried to blow through it and suck through it with mouth, - its open at all times, until I put 6volts to it, then it closes up. then I also tried 12volts, - it also closes up. as soon as I let the power off, it opens up. My question is - does this particular model have completely opposite way the solinoid valve works? I found that the EGR valve is open about half way at idle. I imagine some vacum is lost through the purge control valve, which tees off between the solinoid valve and the EGR valve , then goes back into the manifold.
Submitted: 1 year ago.
Category: Mitsubishi
Customer: replied 1 year ago.
If I close the line leading to the controller, the EGR valve opens up all the way instead of just half. when I accelerate the valve moves towards the closed position only while the engine is picking up the rpms(1/2 second). this only happens with everything connected like it should, but when I plug the line that tees off to the purge control valve nothing moves while accelerating
Customer: replied 1 year ago.
I think I found an answer. please cancel my order. thanks
Customer: replied 1 year ago.
I guess I didn't , because now I know that my solinoid valve is good. I guess there is an issue with the computer or something?
Expert:  Ron replied 1 year ago.

Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

The code P0401 can be set due to any of the following,

  • Exhaust Gas Recirculation (EGR) Solenoid
  • Restricted Orifice
  • Vacuum Hose

    In order to determine which is failing you are going to need to check a few things, see the steps in the link below, copy and paste the link to your browser to open and view them.

    Customer: replied 1 year ago.
    first off, before I posted my question a messege came up saying that an expert is ready to answer , he is an employe of mitsubishi dealership. Also when I was posting the question , there was a timer for me not to loose that expert. Then there was a promise of an appointment... Anyway now I know how operates. first bunch of promises, then completely something else. Now to you Ron- you did not read my findings . you are asking me to check 1. Try blowing through the Exhaust Gas Recirculation (EGR) solenoid with it disconnected, it should flow freely. . Thanks, ***** ***** will try other means of finding an answer first.