GM Service Manual Online
For 1990-2009 cars only

Object Number: 1455573  Size: MF
Master Electrical Component List
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice
Control Module References

Circuit Description

The torque converter clutch pulse width modulation (TCC PWM) solenoid valve controls fluid acting on the converter clutch valve, which then controls TCC apply and release. The TCC PWM solenoid valve attaches to the control valve body within the transmission. Ignition voltage goes directly to the TCC PWM solenoid valve. The powertrain control module (PCM) controls the TCC PWM solenoid valve by providing a ground path on the control circuit. The current flows through the TCC PWM solenoid valve coil according to the duty cycle, percentage of ON time. The TCC  PWM solenoid valve provides a smooth engagement of the torque converter clutch by operating on a duty cycle percent of ON time.

If the PCM detects a continuous open or short in the TCC PWM solenoid valve circuit or the TCC PWM solenoid valve, then DTC P2761 sets. DTC P2761 is a type C DTC. For California emission vehicles, DTC P2761 is a type B DTC.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2761 Torque Converter Clutch (TCC) Pressure Control (PC) Solenoid Control Circuit

Conditions for Running the DTC

    • The system voltage is 8-18 volts.
    • The engine is running greater than 400 RPM for greater than 7 seconds.

Conditions for Setting the DTC

All conditions for running the DTC are met, and either of the following conditions occur for 4.3 seconds out of 5 seconds:

    • The PCM commands the TCC PWM solenoid valve to OFF, 0 percent, and the voltage input remains low, zero volts.
    • The PCM commands the TCC PWM solenoid valve to ON, 100 percent, and the voltage input remains high, B+.

Action Taken When the DTC Sets

    • For California emission equipped vehicles, the PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
    • The PCM inhibits TCC engagement.
    • The PCM commands increased line pressure.
    • The PCM freezes transmission adaptive functions.
    • The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame, California only, and Failure Records, California and Federal.
    • The PCM stores DTC P2761 in PCM history.

Conditions for Clearing the MIL/DTC

    • For California emissions, the PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
    • A scan tool can clear the MIL/DTC.
    • For California emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring.
    • For Federal emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
    • The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.

Diagnostic Aids

DTC P2761 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests for voltage to the solenoid.

  2. This step tests the ability of the PCM and wiring to control the ground circuit.

  3. This step tests the resistance of the TCC PWM solenoid valve and the automatic transmission wiring harness assembly.

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 Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM.

  4. Record the DTC Freeze Frame and Failure Records.
  5. Clear the DTC.

Is DTC P0753 or P0758 also set?

--

Go to Step 3

Go to Step 4

3

Inspect the IGN 0 fuse for an open. Refer to Circuit Protection - Fuses in Wiring Systems.

Is the fuse open?

--

Go to Step 11

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the AT inline 20-way connector. Additional DTCs may set.
  3. Install the J 44152 jumper harness (20 pins) on the engine side of the AT inline 20-way connector.
  4. Turn ON the ignition, with the engine OFF.
  5. Using the J 35616 GM terminal test kit, connect a test lamp from terminal E of the J 44152 to ground. Refer to Automatic Transmission Inline 20-Way Connector End View .

Does the test lamp illuminate?

--

Go to Step 5

Go to Step 14

5

  1. Connect a test lamp between terminal E and terminal S of the J 44152 . Refer to Automatic Transmission Inline 20-Way Connector End View .
  2. Use the scan tool in order to command the TCC PWM solenoid valve ON and OFF three times.

Does the test lamp turn ON and OFF with each command?

--

Go to Step 7

Go to Step 6

6

Is the test lamp always ON?

--

Go to Step 15

Go to Step 16

7

  1. Install the J 44152 on the transmission side of the AT inline 20-way connector.
  2. Using the DMM and the J 35616 , measure the resistance between terminal E and terminal S of the J 44152 . Refer to Automatic Transmission Inline 20-Way Connector End View .

Does the resistance measure within the specified range?

10-15 ohms

Go to Step 8

Go to Step 9

8

Measure the resistance from terminal E to ground, and from terminal S to ground.

Do both readings measure greater than the specified value?

250 K ohms

Go to Intermittent Conditions in Engine Controls - 4.8L, 5.3L, and 6.0L

Go to Step 10

9

  1. Disconnect the AT wiring harness assembly from the TCC PWM solenoid valve.
  2. Measure the resistance of the TCC PWM solenoid valve.

Does the resistance measure within the specified range?

10-15 ohms

Go to Step 17

Go to Step 18

10

  1. Disconnect the AT wiring harness assembly from the TCC PWM solenoid valve.
  2. Measure the resistance from each of the component terminals to ground.

Do both readings measure greater than the specified value?

250 K ohms

Go to Step 17

Go to Step 18

11

Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems for complete circuit distribution.

Test the Ignition 0 voltage circuit of the TCC PWM solenoid valve for a short to ground between the fuse block and the AT inline 20-way connector. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 12

12

Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems for complete circuit distribution.

Test the Ignition 1 voltage circuit of the TCC PWM solenoid valve for a short to ground between the AT inline 20-way connector and the TCC PWM solenoid valve. Refer to Testing for Short to Ground in Wiring Systems.

Did you find a short to ground condition?

--

Go to Step 17

Go to Step 13

13

  1. Test each solenoid for a short to ground.
  2. Replace the faulty solenoid as necessary.

Did you complete the replacement?

--

Go to Step 20

--

14

Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems for complete circuit distribution.

Test the Ignition 0 voltage circuit of the TCC PWM solenoid valve for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

--

15

Test the control circuit of the TCC PWM solenoid valve for a short to ground between the PCM connector C2 and the AT inline 20-way connector. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 19

16

Test the control circuit of the TCC PWM solenoid valve for an open or short to power between the PCM connector C2 and the AT inline 20-way connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 19

17

Replace the AT wiring harness assembly. Refer to Valve Body and Pressure Switch Replacement .

Did you complete the replacement?

--

Go to Step 20

--

18

Replace the TCC PWM solenoid valve. Refer to Valve Body and Pressure Switch Replacement .

Did you complete the replacement?

--

Go to Step 20

--

19

Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, set-up, and programming.

Did you complete the replacement?

--

Go to Step 20

--

20

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Drive the vehicle in D4 with the TCC On. Ensure that the following conditions are met:
  4. • The PCM commands the TCC PWM solenoid valve ON, and the voltage feedback drops to zero.
    • The PCM commands the TCC PWM solenoid valve OFF, and the voltage feedback increases to B+.
    • All conditions are met for 5 seconds.
  5. Select Specific DTC.
  6. Enter DTC P2761.

Has the test run and passed?

--

Go to Step 21

Go to Step 2

21

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