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engine failsafe mode...

Discussion in 'General Discussion' started by anthony d, May 9, 2010.

  1. anthony d

    anthony d Member

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    hello all, first thread here...

    did a search, didn't find anything relevant to my situation.

    ok, so here is the deal. i have a 2006 expedition limited, with a tad over 53k miles. while i was driving at approximately 65mph the other night, i noticed the speedo needle was starting to drop, and then go back to the speed i was traveling. looked at all the other gauges, and everything was fine. engine temp was fine, battery was fine, oil pressure was fine. shortly after that (within a minute or so), the check engine light came on, the display said "engine failsafe mode", the "o/d off" light started flashing, and the speedo dropped to 0. the engine went into limp mode, so i pulled over to the side of the road to check things out. there was plenty of coolant, oil was full, transmission fluid was full.

    so i started the motor again, and it was the same. "engine failsafe mode" showed on the display, the check engine light was on, the "o/d off" light was flashing, and the engine was in limp mode. i was about an hour from home, so i called a tow truck, and got the truck home.

    i looked in the manual for "failsafe mode", but the only thing i could find had to do with the engine overheating, or being low on coolant, which it wasn't.

    any ideas on what it could be?
     
  2. KWT2000

    KWT2000 Full Access Members

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    it sounds like a faulty engine temp sensor for the ECM... there are seperate sensor for the gauge
     
  3. anthony d

    anthony d Member

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    i'll check that out, thanks! is there anywhere i can download a pdf of the factory service manual for the truck?
     
  4. anthony d

    anthony d Member

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    ok, so i borrowed an obd2 code scanner from a buddy, and got 2 codes. i got P0720, which appears to be a speed sensor issue, and P2106, which appears to be a throttle actuator control system issue.

    any advice? can i just replace the speed sensor and the throttle position sensor? can't be that easy, right?
     
  5. anthony d

    anthony d Member

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    ok, so with some more research, i came to the conclusion that the p0720 code (oss) is a detail of the p2106 (etc) code. so i am thinking it is safe to assume that my issue is with the output shaft speed sensor...
     
  6. jv2000

    jv2000 Member

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    Get yourself a nice (and more importantly inexpensive) code reader so you don't have to borrow it from your friend. Seriously it'll pay for itself in a jiffy

    Here's a good one for cheap...

    [​IMG]
    Autel MaxiScan MS300 OBDII Scan Tool[​IMG]
     

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