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OBD II, won't start PLEASE HELP

Discussion in 'The Garage' started by SUBFAN, Nov 28, 2005.

  1. SUBFAN

    SUBFAN 1/2 ton status

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    1998 Olds Bravada....

    It is throwing a code P1351-IDM input circuit malfunction/Ignition control circuit, high voltage....

    (IDM stands for Ignition Diagnostic Monitor)

    I have ruled out the coil, replaced the ignition control module, checked for spark at the cylinder, and it just wont start....

    This vehicle is equipped with a crank AND a cam position sensor. Could these be giving bad readings throwing off the timing or something?

    The book does not give a check for either of those two position sensors....

    This has got me really confused....Any ideas/suggestions?
     
    Last edited: Nov 28, 2005
  2. SUBFAN

    SUBFAN 1/2 ton status

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    The Crank Position sensor is $130, and you have to remove the front half of the motor to get at it. Obviously looking for ways around that.... :whistle: :whistle: :whistle: :whistle:
     
  3. SUBFAN

    SUBFAN 1/2 ton status

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  4. dyeager535

    dyeager535 1 ton status Premium Member

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    What book are you looking in? Is it something that walks you through the code diagnosis, or just points to potential problems?

    I have no experience with OBD2, but are some of the potential problems things a scanner will let you "see" to ensure they are at least working? I know autozone has scanners you can use, but if you can't get the vehicle there, they probably don't let you borrow them...be the cheapest way if they would though!
     
  5. 84zz4ss

    84zz4ss 1/2 ton status Premium Member

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    P1351

    DTC P1351 Ignition Coil Control Circuit High Voltage

    Are you able to read engine data?

    Crank sensor takes one bolt to change. After removing engine splash shields.

    Pm me for more detail.
     
  6. SUBFAN

    SUBFAN 1/2 ton status

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    I am considering the purchase of a code 'reader.' Any suggestions on brands?

    How does this one bolt trick work? Is there a test to perform if this is operating correctly?

    I haven't investigated its location yet.

    Thanks....
     
  7. SUBFAN

    SUBFAN 1/2 ton status

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    OBD II Won't start (Update)

    Both the Chilton and Haynes leave somethings to be desired. I have a print out from someone that is more 'step by step' on the offending trouble code....

    We borrowed the scanner to get that code, but that is just a freeze frame thing. It sucks using it then returning it only to find out you were not through with it.... :doah: :doah: :doah: :doah:

    Replaced the Crank Position Sensor, and the code went away....

    Still no start....
     
    Last edited: Nov 30, 2005
  8. SUBFAN

    SUBFAN 1/2 ton status

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    Replaced the Crank Position Sensor, and the code went away....

    Still no start....
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    You've checked spark, are you getting fuel? (injector pulse, pressure, etc)
     
  10. SUBFAN

    SUBFAN 1/2 ton status

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    The pressure is there, and a spark plug smelled like gas. I need to really verify that fuel is actually being entered into the equation.

    I am going to introduce some gas into the throttle body and see if that helps.

    Long process working all day, then watching the kids while she is at work. Plus it is not even at the house or shop....
     
  11. Thunder

    Thunder 3/4 ton status

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    If you dont mind paying $5.00. Go herehttp://codetrack.spx.com/
    For 5 bucks you can look up 3 codes. they give all the details on the code as what componets fail that can throw the code + trouble shooting and repair.
     
  12. SUBFAN

    SUBFAN 1/2 ton status

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    Saved.... :D
     
  13. SUBFAN

    SUBFAN 1/2 ton status

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    :haha: :haha: :haha: :haha: Won't accept P 1351.... :haha: :haha:
     
  14. Thunder

    Thunder 3/4 ton status

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    Yeah they are getting the database together so they dont have all the codes in. Sorry.
    I am not real up on OBD 2 but check the wreing between the Ignition module and the computer. Make sure all the connections are good.
    Copyed this maby it will help:
    Code P1351 Ignition Control (IC) Circuit High Voltage.
    Diagnostic will set when the following conditions are met:
    Voltage on IC circuit is greater than 4.9 volts and engine speed is less than 250 RPM.
    Basically the engine is either at rest or cranking when the VCM (PCM) is monitoring for the high voltage diagnstic.
    The VCM has an internal 5 volt reference that's used for several circuits. This voltage is dropped across a resistor and fed to the corresponding control circuit. The VCM monitors this voltage to determine circuit integrity.
    You could have a wiring problem between the ICM (ICU) and VCM, or a problem with the connector(s) at either the ICM or VCM, or the VCM is going bad.
    For this problem a wiring diagram is your friend. You can check the connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, or rubbed through wire(s).
    Check the ICM to VCM wiring very close.
    A good way to find a wiring problem is to clear the code. Monitor the reference voltage while having someone pull on wiring at the VCM/ICM and wiggling the harnesses. If this makes the voltage to go high you know it's a wiring problem. If the voltage remains constant and the code RESETS than the VCM is the problem.
     
  15. SUBFAN

    SUBFAN 1/2 ton status

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    Thanx, and damn, I hate wires....
     

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