2010 08 12 185619 2007 Cadillac CTS fourth gear only by 2jEJEK

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									PATH: Diagnostics > Diagnostic Routines > Powertrain > Automatic Transmission -
5L40-E/5L50-E > DTC P2764
    DTC P2764

                                        NOTE




                              Applicable vehicles:
                                      CTS (VIN D)

    DTC P2764




                                 Click to Enlarge
    Circuit Description
    The transmission control module (TCM) provides voltage to the torque
    converter clutch pulse width modulated (TCC PWM) solenoid valve through
    High Side Driver 2 (HSD2). The TCM controls the ON and OFF time of the
    solenoid by providing a ground through the output driver module (ODM). The
    TCM uses a PWM duty cycle, in order to control application and release of the
    TCC. When the solenoid is commanded OFF, the TCM senses high voltage.
    When the solenoid is commanded ON, the TCM senses low voltage.
    When the TCM detects a continuous open or short to ground in the TCC PWM
    Solenoid valve circuit, then DTC P2764 sets. DTC P2764 is a type B DTC.
    DTC Descriptor
    This diagnostic procedure supports the following DTC:
DTC P2764 Torque Converter Clutch (TCC) Pressure Control (PC) Solenoid
Control Circuit Low Voltage
Conditions for Running the DTC
              The engine run time is greater than 5 seconds.
              HSD2 is commanded ON.
Conditions for Setting the DTC
DTC P2764 sets when either of the following conditions occurs:
              The TCM detects an open in the TCC PWM solenoid valve
                 circuit when the PWM duty cycle is greater than 20 percent.
              The TCM detects a short to ground in the TCC PWM solenoid
                 valve circuit when the PWM duty cycle is greater than 20
                 percent but less than 50 percent.
Action Taken When the DTC Sets
              The TCM requests the ECM to illuminate the malfunction
                 indicator lamp (MIL) during the second consecutive drive trip
                 in which the Conditions for Setting the DTC are met.
              The TCM turns off power to all solenoids. When the solenoids
                 are off:
                                The transmission will operate in fifth gear if
                                   the vehicle has successfully completed a 1-2
                                   upshift in the current ignition cycle. If the
                                   vehicle has not completed a 1-2 upshift in the
                                   current ignition cycle, the transmission will
                                   operate in fourth gear. If the transmission is
                                   operating in fifth gear, fourth gear may be
                                   obtained if the engine is stopped briefly and
                                   started again.
                                The line pressure is at maximum.
              The TCM freezes transmission adaptive functions.
              At the time of the first failure, the TCM records the operating
                 conditions when the Conditions for Setting the DTC are met.
                 The TCM stores this information as a Failure Record.
              At the time of the second failure, the ECM records the
                 operating conditions when the Conditions for Setting the DTC
                 are met. The ECM stores this information as a Freeze Frame.
              The TCM stores DTC P2764 in TCM history.
Conditions for Clearing the MIL/DTC
              The ECM turns OFF the MIL after the sixth consecutive drive
                 trip in which the TCM does not send a MIL illumination
                 request.
              A scan tool can clear the MIL/DTC.
                      The TCM clears the DTC from TCM history if the vehicle
                       completes 40 warm-up cycles without an emission related
                       diagnostic fault occurring.
                    The TCM cancels the default actions when the ignition is OFF
                       long enough in order to power down the TCM.
       Test Description
       The number below refers to the step number on the diagnostic table.
               2. Listen for a soft rattling sound when the solenoid energizes. Use a
                   stethoscope if necessary.

Step                         Action                       Value(s)      Yes         No
       Did you perform the Diagnostic System Check -                            Go to
       Vehicle?                                                                 Diagnostic
 1                                                            --                System
                                                                     Go to Step Check -
                                                                         2      Vehicle
                       1. Install a scan tool.
                       2. Turn ON the ignition with
                          the engine OFF.

                             WARNING




                    Important:
                            Before clearing
                           the DTC, use the
                           scan tool in order
                           to record the
                           ECM Freeze
                           Frame and the
 2                         TCM Failure                        --
                           Records. Using
                           the Clear Info
                           function erases
                           the Freeze Frame
                           and Failure
                           Records from the
                           ECM and the
                           TCM.
                            Using the Clear
                           Info function
                           erases stored
                           DTCs in both the
                           ECM and TCM.                              Go to Step Go to Step
                                                                         9          3
Step                    Action                       Value(s)      Yes        No
                3. Record the DTC Freeze
                    Frame and Failure Records.
                4. Clear the DTC.
                5. Use the scan tool in order to
                    command the TCC PWM
                    solenoid ON.
       Does the solenoid operate?
                1. Turn OFF the ignition.
                2. Disconnect the AT 20-way
                    inline harness connector.
                3. Install the J 45681 jumper
                    harness to the TCM side of
                    the 20-way connector.
 3              4. Turn ON the ignition with            --
                    the engine OFF.
                5. With the test lamp
                    connected to ground, probe
                    the HSD2 circuit, terminal
                    17, of J 45681 .                            Go to Step Go to Step
       Does the test lamp illuminate?                               4          7
                  1. Turn OFF the ignition.
                  2. Install the J 45681 to the
                      transmission side of the 20-
                      way connector.
                  3. Using the DMM, measure
                      the resistance between          10.0-
 4
                      terminal 17 and 20 of the J     13.6?
                      45681 .
                      Refer to Component
                      Resistance.
       Is the resistance within the specified                   Go to Step Go to Step
       range?                                                       5          8
       Using the DMM, measure the resistance
       between terminal 17 of the J 45681 and
 5     ground.                                        50K ?
       Is the resistance greater than the                       Go to Step Go to Step
       specified value?                                             6          8
                1. Disconnect the TCM.
 6              2. Test the TCC PWM                     --      Go to Step Go to Step
                   solenoid valve control                           10         9
Step                    Action                      Value(s)      Yes        No
                    circuit for the following
                    conditions:
                         Open circuit
                         Short to ground
                         Refer to Testing for
                             Continuity and
                             Testing for Short to
                             Ground.
       Did you find a condition?
                1. Turn OFF the ignition.
                2. Disconnect the TCM.
                3. Test the HSD2 circuit from
 7                  the TCM to the TCC PWM             --
                    solenoid for an open circuit.
                    Refer to Testing for
                    Continuity.                                Go to Step Go to Step
       Did you find a condition?                                   10         9
                1. Remove the transmission
                    oil pan.
                2. Test the TCC PWM
                    solenoid wiring from the
                    20-way connector to the
                    TCC PWM solenoid
                    connector for the following
 8                  conditions:                        --
                         Open circuit
                         Short to ground
                         Refer to Testing for
                             Continuity and
                             Testing for Short to
                             Ground.                           Go to Step Go to Step
       Did you find a condition?                                   11         12
       Replace the TCM.
       Refer to Control Module References
 9                                                     --                     --
       for replacement, setup and programming.                 Go to Step
       Is the action complete?                                     13
       Perform the necessary wiring repairs.
10     Refer to Wiring Repairs.                        --      Go to Step     --
       Is the action complete?                                     13
Step                   Action                      Value(s)      Yes        No
       Replace the AT internal transmission
       wiring harness.
11     Refer to Transmission Internal Electrical      --                     --
       Harness Replacement.                                   Go to Step
       Is the action complete?                                    13
       Replace the TCC PWM solenoid valve.
       Refer to Torque Converter Clutch
12                                                    --                     --
       Solenoid Replacement.                                  Go to Step
       Is the action complete?                                    13
       Perform the following procedure in order
       to verify the repair:
                 1. Select DTC.
                 2. Select Clear Info.
13               3. Turn ON the ignition, with        --
                     the engine OFF.
                 4. Select Specific DTC.
                 5. Enter DTC P2764.                          Go to Step Go to Step
       Has the test run and passed?                               14         2
       With the scan tool, observe the stored                 Go to
       information, capture info and DTC info.                Diagnostic
       Does the scan tool display any DTCs that               Trouble
14     you have not diagnosed?                        --      Code
                                                              (DTC)
                                                              List -       System
                                                              Vehicle       OK

								
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