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    Guest Message by DevFuse
     

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    mac granite cv713 electrical issue



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    1 reply to this topic

    #1 OFFLINE   rnmech40

    rnmech40

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    Posted 13 December 2013 - 01:50 PM

    im working on and intermittent electrical issue. about 2 times a day it will lose all throttle response and a lighning bolt coms up on the dash. the codes i get off the instrument cluster is a p091-04 m142. from my research this is app low voltage. is this correct? it has a brand new app assymbly in it. now the truck has actually stayed in tennis shoe mode any one ever had this problem or can get me in the right direction.



    #2 OFFLINE   turckster

    turckster

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    Posted 17 December 2013 - 10:50 PM

    From Mack Electronic Info System:

     

    When performing electrical tests, wiggle wires and connectors to find intermittent problems.

    Failure Mode Identifier (FMI): 3 (Voltage High), 4 (Voltage Low/Open), 14 (Invalid)

    Parameter Identification (PID): P91

    Message Identification (MID): 142

    Circuit Description: The Throttle Position (TP) Sensor is a potentiometer that is mechanically linked to the accelerator pedal. When the accelerator pedal is depressed during normal operation, the TP Sensor signal voltage to the Vehicle Electronic Control Unit (VECU) increases. The Vehicle Electronic Control Unit (VECU) monitors the TP Sensor signal voltage and uses the signal to calculate engine fuel requirements.

    Location: The Throttle Position (TP) Sensor is located beneath the accelerator pedal. The TP Sensor pigtail connector is located under the dash above the accelerator pedal. The Vehicle Control Unit (VECU) is typically located under the dashboard in front of the passenger seat.

    Code Setting Conditions: The Electronic Malfunction Lamp (EML) will turn on and code 5-1 will set when the Vehicle Electronic Control Unit TP Sensor signal voltage is less than 0.4 volts or greater than 4.5 volts for 0.25 seconds. If the signal voltage returns to between 0.4 volts and 4.5 volts for 0.25 seconds, the fault will become inactive. When code 5-1 is active, engine speed will default to 900 RPM.

    Additional Symptoms: Accelerator pedal is unresponsive. Engine stumbles if the fault is intermittent.

    Normal TP Sensor Parameters:


    Table 1

    Resistance pin C to pin A

    2000–3000 Ω

    Resistance pin C to pin B

    200–800 Ω (accelerator pedal not depressed)

    Resistance pin C to sensor case

    Over 100,000 Ω

       

     

    Remove the vecu kick panel, make sure none of the wiring is damaged from rubbing. I think, but not sure,  in the wiring to the vecu (near it) there is a connector for remote throttle. Make sure that the connector(s) are tight. 

     

    Good luck






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