CAR CODES PO401- I HAVE REPLACED THE EGR SOLENOID AND VALVE, A VACUUM HOSE AND THE DPFE SENSOR. THE TUBING AND HOSES HAVE BEE CLEANED OF ANY CARBON BUILD UP AND THE INTAKE HAS BEEN CHECKED YET THE SERVICE ENGINE LIGHT CONTINUES TO COME BACK ON WITH THE SAME CODE PO401. WHAT ELSE CAN I DO ??? MY MITSUBISHI ECLIPSE CANNOT PASS THE STATES REQUIRED EMISSIONS TEST. PLEASE HELP DESPERATE FOR ANSWERS!!!
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2001 Mitsubishi Eclipse Question: CHECK ENGINE LIGHT CONTINUES TO COME ON AND SHOWS A CODE OF PO401 WHAT CAN I DO
Answer #1mastertech6371 October 11, 2011, 11:02Master
did you have a real diag from a real shop??? lots of aprts and no results.
the dpfe is the most common but the pcm has to ground the egr solenoid to make the system work. you need to verify that it is doing that. without a scan tool, that would be tough. the solenoid may have been your only issue but you need to confirm.
ReplyEGEISMAR, October 11, 2011, 12:43Rookie
Thanks for your response. I have used reputable mechanics from the Mitsubishi Dealership and Precision Auto Care. Mitsubishi I feel was a MONEY PIT...I spent over $400 for them to misdiagnose the problem twice. Precision has really worked hard to find the problem and have now stoped charging for their time and labor. This has been going on for months of trying to find the problem. Precision has corrected the rough idling and the car is driving fine, but the service engine light continues to come back on with the same code of PO401. That is why I am searching for answers.I need to pass the emissions test by the end of this month to get my tags!!!!
Replymastertech6371, October 11, 2011, 13:31Master
I had to ask the question as we can assume nothing here at all. sorry if I offended you.
going back to the solenoid, you do need to see if it has a ground in the pcm. if the old one was shorted out, it could have taken out the pcm.
pin point testing can verify the operation. you can use a test light on the ground side and see if it opens and the egr operates by the idle change. beyond that, you need a shop with a scan tool to do it through there.