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2001 Mercury Mountaineer P1409: Idle Fluctuation and Check Engine Light with Vacuum Regulator Fault

Model: 2001 Mountaineer Fault Code: P1409 Posted: 2009-07-01 09:47

I own a 2001 Mercury Mountaineer and am experiencing inconsistent idle behavior—my engine fluctuates between high and low RPMs, and at times actually stalls when idling. This issue has persisted for about two weeks, and yesterday the check engine light activated with OBD-II diagnostic code P1409, indicating a fault in the Electronic Vacuum Regulator Control Circuit. I came across an earlier post discussing this same code on a Ford vehicle, where users were advised to locate the EGR vacuum regulator by tracing the vacuum lines. The response mentioned that the regulator typically has red and green colored hoses. I'm wondering if this information applies to my 2001 Mercury Mountaineer as well. Can someone confirm whether the vacuum regulator in my model has red and green vacuum lines, and if it features a two-pin electrical connector?

Related fault codes
P1409
Comments (2)
Anonymous 2009-07-01 16:54

Yes, the EGR vacuum regulator on your 2001 Mercury Mountaineer typically has red and green vacuum hoses. It is usually made of hard plastic and includes a two-pin electrical connector. This setup is consistent across many vehicles in this model range, including the Mountaineer.

Anonymous 2009-07-02 06:07

Thanks for the clarification—this helps me diagnose the issue. I’m actually looking forward to the 4th of July now that I know what’s causing the idle problem!