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engine code p1151

Discussion in 'Transmission & Drive train' started by jrmustang, May 7, 2010.

  1. jrmustang

    jrmustang New Member

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    i have a 2000 ford expedition 5.4 and after doing a complete tune up (plug,wire,vac hose,filters and pvc)and put headers and dual exhaust on. i discovered that check engine light is either blown or unplug (bought at a used car dealer).so it was running funny, ran the codes and got P1151.i was wondering if an exhaust leak at the header to the down pipe before the first o2 sensor would cause this?

    I'm having a hard time getting the exhaust to seal up any info will
    help thanks
     
  2. tonydiv

    tonydiv technical advisor

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    This is from obd-codes.com

    What does that mean?: A Heated Exhaust Oxygen (HO2S) sensor indicating lean at the end of a test is trying to correct for an over-rich condition. The test fails when the fuel control system no longer detects switching for a calibrated amount of time.

    Symptoms: You will likely not notice any drivability problems.

    Causes: A code P1151 may mean that one or more of the following has happened:

    Electrical:
    Short to VPWR in the harness or HO2S
    Water in the harness connector
    Open/shorted HO2S circuit
    Corrosion or poor mating terminals and wiring
    Damaged HO2S
    Damaged PCM

    Fuel System:
    Excessive fuel pressure
    Leaking/contaminated fuel injectors
    Leaking fuel pressure regulator
    Low fuel pressure or running out of fuel
    Vapor recovery system

    Induction System:
    Air leaks after the MAF
    Vacuum Leaks

    PCV system:
    Improperly seated engine oil dipstick

    EGR System:
    Leaking gasket
    Stuck EGR valve
    Leaking diaphragm or EVR

    Base Engine:
    Oil overfill
    Cam Timing
    Cylinder compression
    Exhaust leaks before or near the HO2S(s)
     
    Last edited: May 7, 2010
  3. jrmustang

    jrmustang New Member

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    it has been running rich, back firing, and hesitent in lower rpms im going to get the exhuast leak fixed this week and erease the codes. But how do i test the o2 censors to make sure they are sending the correct signal. what would be the next step that you would do?
     
  4. seeker

    seeker Full Access Members

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    I am not sure of any test that you can do on the o2 sensor. With that said, I have replaced my share of them. They fail and start to send a lean code to your computer. The computer adjustes to a richer fuel/air mix. This could explain your back firing. Change the o2 sensor. Visually check the wirring and connection. If it looks good, I am placing my bet that the o2 swap will correct you problem.
     
  5. jrmustang

    jrmustang New Member

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    that sound like the source of my problem i will have to work on it this week and will let you know if it was. I'm all most positive that's it. Thanks for the help
     

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