P1233 Code But No Symptoms...?

Discussion in 'SN95 4.6L Mustang Tech' started by Taylor Gill, Oct 10, 2013.


  1. Taylor Gill

    Taylor Gill Member

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    Hey guys, I've got a 2000 gt and recently used my predator to check my codes due to no cats and adjust the speedometer for the 4.10 gear. Anyway, it's throwing a p1233 code, saying the FDPM is disabled or offline. I've searched and searched and it seems the symptoms other people are having with this code...I'm not having. Power seems good and no idle problems or stalling. Also engine light doesn't come on. I've tried clearing it and it keeps coming back. But like I said, no noticeable problems. I don't own a voltmeter or I'd test it. Does anybody have any input or should I just ignore it? haha Thanks in advance!
     
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  2. COramprat

    COramprat Drone Driver
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    Could be the sensor on the verge of going bad. Buy a volt meter and test it. They are cheap.
     
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  3. COramprat

    COramprat Drone Driver
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    Check this explanation.


    Discussion from the PCED:

    P1233 - Fuel System Disabled or Offline
    Description:

    The PCM monitors the fuel pump monitor (FPM) circuit from the fuel pump driver module (FPDM). With the key on, the FPDM continuously sends a duty cycle signal to the PCM through the FPM circuit. The test fails if the PCM stops receiving the duty cycle signal.

    Possible causes:

    Inertia fuel shutoff (IFS) switch needs to be reset
    Open FPDM ground circuit
    Open circuit to FPDM PWR RLY
    Open FPDM PWR circuit
    Open or shorted FPM circuit (engine should start)
    Damaged IFS switch
    Damaged FPDM PWR RLY
    Damaged FPDM
    Damaged PCM

    Diagnostic aids:

    The PCM expects to see one of the following duty cycle signals from the FPDM on the FPM circuit: 1) 50% (500 ms on, 500 ms off), all OK. 2) 25% (250 ms on, 750 ms off), FPDM did not receive a fuel pump (FP) duty cycle command from the PCM, or the duty cycle that was received was invalid. 3) 75% (750 ms ON, 250 OFF), the FPDM has detected a fault in the circuits between the FPDM and the fuel pump.

    /////End C & P ////




    What that means is that the PCM is not receiving its feedback signal from the FPDM that is supposed to let the PCM know how the FPDM is performing.
     
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  4. Taylor Gill

    Taylor Gill Member

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    Awesome, thanks a lot! I also remember reading somewhere on how to actually test it through the connector or something. I'll have to rummage through my browser history. I just wanted to post to get ideas on it I guess.
     
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  5. Taylor Gill

    Taylor Gill Member

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    I used my tuner to check diagnostics and it shows 26.18% - 29.98% and the fpd will show it kicks on and off but not sure how quick it switches. So I guess I'm looking at the right stuff. I'm assuming this will be under number 2 of the 3 duty cycles. So would this be considered a fuel pump problem, connection or the fpdm?
     
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  6. Taylor Gill

    Taylor Gill Member

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    Let me correct myself, I turned the key on instead of starting the engine and check my diags again...this time it's dead on 75% so it's a faulty connection between it and the fuel pump. Does anyone happen to know which wires to test? I've searched but can't find much on FPDM to fuel pump wiring.
     
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  7. COramprat

    COramprat Drone Driver
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    Not sure from here. Maybe one of the techs that come here can find something but I'm thinking a bad sensor since you have no other issues.
     
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  8. Taylor Gill

    Taylor Gill Member

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    I appreciate the help man! I went ahead and replaced the FPDM and it stills shows the code but no check engine light. I do remember unplugging the inertia switch when I changed my fuel filter. I did reset the switch, but would it keep the code in memory like it has? And I've yet to use my volt meter yet.
     
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  9. COramprat

    COramprat Drone Driver
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    The code stays in the memory until erased. You have it reset with a code reader or disconnect the battery.
     
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