GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 STS 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 5L40-E/5L50-E 🢒 DTC P2764

Object Number: 1466342 Size: MF
Master Electrical Component List
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice
Control Module References

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 occur for 4.3 seconds:

    • 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.
    • 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.
    • The TCM commands maximum line pressure.
    • The TCM freezes transmission adaptive functions.
    • The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
    • The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
    • The TCM stores DTC P2764 in TCM history.

Conditions for Clearing the MIL/DTC
    • The ECM turns OFF the MIL after the third 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.

  1. Listen for a soft rattling sound when the solenoid energizes. Use a stethoscope if necessary.

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.

    3. Important: 

       • Before clearing the DTC, use the scan tool in order to record the ECM Freeze Frame and the 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.

  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?

--

Go to Step 9

Go to Step 3

3
  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.
  4. Turn ON the ignition with the engine OFF.
  5. With the test lamp connected to ground, probe the solenoid supply voltage circuit of J 45681 .

Does the test lamp illuminate?

--

Go to Step 4

Go to Step 7

4
  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 the solenoid supply voltage circuit and the TCC PWM solenoid valve control circuit of the J 45681 .

    4. Refer to Component Resistance .

Is the resistance within the specified range?

10.0-13.6ohms

Go to Step 5

Go to Step 8

5

Using the DMM, measure the resistance between the solenoid supply voltage circuit of the J 45681 and ground.

Is the resistance greater than the specified value?

50K ohms

Go to Step 6

Go to Step 8

6
  1. Disconnect the TCM.
  2. Test the TCC PWM solenoid valve control circuit for an open or short to ground.

Refer to Testing for Continuity and Testing for Short to Ground in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

7
  1. Turn OFF the ignition.
  2. Disconnect the TCM.
  3. Test the solenoid supply voltage circuit and the solenoid valve control circuit from the TCM to the TCC PWM solenoid valve for an open circuit. Refer to Testing for Continuity in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

8
  1. Remove the transmission oil pan.
  2. Test the solenoid supply voltage circuit and the solenoid valve control circuit from the 20-way connector to the TCC PWM solenoid valve connector for an open or short to ground.

Refer to Testing for Continuity and Testing for Short to Ground in Wiring Systems.

Did you find a condition?

--

Go to Step 10

Go to Step 11

9

Replace the TCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Is the action complete?

--

Go to Step 12

--

10

Replace the AT internal transmission wiring harness. Refer to Transmission Internal Electrical Harness Replacement .

Is the action complete?

--

Go to Step 12

--

11

Replace the TCC PWM solenoid valve. Refer to Torque Converter Clutch Solenoid Replacement .

Is the action complete?

--

Go to Step 12

--

12

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Start the engine.
  4. Drive the vehicle with the TCC Duty Cycle above 36% for 5 seconds.
  5. Select Specific DTC.
  6. Enter DTC P2764.

Has the test run and passed?

--

Go to Step 13

Go to Step 2

13

With the scan tool, observe the stored information, capture info and DTC info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

System OK