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1996 Suburban 4x4 1500 P1700 Code

Discussion in 'GM Powertrain' started by barryT, May 11, 2009.

  1. barryT

    barryT New Member

    I have had this code come up a few times. When I reset the computer it doesn't illuminate for a while. I realize its a TCM error code, but the transmission is shifting great. No difference between when the code wasn't come on. Is there anything besides a bad TCM that it could be? If it is the TCM where could I find one? How much do they usually run?

    -barry
  2. barryT

    barryT New Member

    Does any one have an idea?
  3. GaryL

    GaryL New Member ROTM Winner Platinum Contributor 1000 Posts

    I found the following on a Cadillac site:

    Your Transmission Control Module is NOT necessarily bad. As a matter of fact, it is probably doing its job just fine by sending this code to the ECM.
    Here is what the manual says for this particular code:
    DTC P1700 Transmission Control Module (TCM) Requested MIL Illumination


    Circuit Description


    This DTC indicates that a transmission related OBD failure has occurred. The Transmission Control Module (TCM) controls a dedicated Service Transmission Lamp (STL) which illuminates when a fail reports by certain non-emissions related TCM diagnostics. The TCM has no direct control of the engine MIL, but if a transmission fault occurs that is emissions related, the engine MIL must illuminate. A MIL Request circuit between the ECM and the TCM provides a means for illuminating the MIL, even though the fault was detected by the TCM. This circuit is pulled up to B+ within the ECM. In order to illuminate the MIL, the TCM pulls the circuit low. The ECM detects this and DTC P1700 is set, which illuminates the MIL.

    Conditions for Running the DTC


    Tested continuously

    Conditions for Setting the DTC


    An OBD II transmission DTC has been stored by the TCM.

    Action Taken When the DTC Sets


    • The ECM illuminates the Malfunction Indicator Lamp (MIL) 1 second after the request from the TCM is received.
    • The ECM records operating conditions at the time the TCM initiates the request. This information will store in the Freeze Frame.
    Conditions for Clearing the MIL/DTC


    • The ECM will turn the MIL off approximately 1 second after the TCM request is no longer received.
    • A History DTC clears after forty consecutive warm-up cycles if no failures report by this diagnostic or any other emission related diagnostic.
    • The ECM battery voltage is interrupted.
    • The scan tool clears the MIL/DTC.
    DTC P1700 - MIL Requested By TCM



    To summarize and translate:
    If you have had this code for some time, then there has been a problem with the transmission that may have started out as a minor problem, but has gotten bad enough so that you notice a problem with shifting.
    The proper way to troubleshoot this type of problem is to have the car connected to a class 2 scan tool (like the dealer uses), so that it can communicate with the transmission control module directly. This is about the only way to find out directly what the problem is. Anything else would be guesswork.
  4. barryT

    barryT New Member

    My suburban seems to be shifting fine. I guess I will take it to the gm dealer and get it scanned.



    -barry
  5. barryT

    barryT New Member

    Well I have an appointment on friday. Lets hope its not too expensive.
  6. GaryL

    GaryL New Member ROTM Winner Platinum Contributor 1000 Posts

    Good luck and let us know what you find out.
  7. barryT

    barryT New Member

    I did find an amazing deal on a burb 2500 with the 4l80e. I might get it next week. Its almost to good to pass up. I just here so many bad things about the dependability of the 4l60e. It might be worth getting a new vehicle.
  8. GaryL

    GaryL New Member ROTM Winner Platinum Contributor 1000 Posts

    It's all about who you talk to. I have 155,000 on mine without a problem.
  9. barryT

    barryT New Member

    I am at 156600 so far. the engine is more then solid.
  10. barryT

    barryT New Member

    Well i guess the trans code that it it gave me a few months back was a fluke. I had a full ispection/diagnostic done on my suburban today and well the code that kept poping up was the bank 1 o2 sensor. Well they wanted 280 dollars to replace it. I am about to head to my Baes shop and do it for the cost of the o2 sensor (47 dollars). I feel lucky that it wasnt the tranmission. One other problem came up. I need to replace my oil seals on my axels. That should be interesting.


    -barry

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