For 1990-2009 cars
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 the fluid acting on the converter clutch valve. The converter clutch valve controls the torque converter clutch (TCC) application and release. The solenoid attaches to the control valve body within the transmission. The solenoid receives ignition voltage through the Ignition 0 voltage circuit. The powertrain control module (PCM) controls the solenoid by providing a ground path on the TCC PWM solenoid valve control circuit. Current flows through the solenoid coil according to the duty cycle, percentage of ON and OFF time. The TCC PWM solenoid valve provides a smooth engagement of the TCC by operating during a duty cycle percent of ON time.

When the PCM 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 speed is greater than 475 RPM for 5 seconds.

• | The engine is not in fuel cutoff.

### Conditions for Setting the DTC

DTC P2764 sets if the following condition occurs for 5 seconds:

The PCM commands the solenoid OFF, 0 percent, and the voltage feedback remains low, 0 volt.

### Action Taken When the DTC Sets

• | 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 inhibits 4th gear if the transmission is in hot mode.

• | 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 and Failure Records.

• | The PCM stores DTC P2764 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

### Conditions for Clearing the MIL/DTC

• | 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.

• | The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.

• | The PCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM.

### 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.

#### DTC P2764

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

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

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 powertrain control module (PCM).

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

Are any of the following DTCs also set?

• | P2769

• | P2770

• | P0973

• | P0974

• | P0976

• | P0977

• | P0787

• | P0788

--

Go to Step 3

Go to Step 4

3 | Inspect the TRANS fuse for an open. Refer to Circuit Protection - Fuses. 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 the ignition voltage circuit 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 the test lamp between the TCC PWM solenoid valve ignition voltage and control circuits 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 3 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 the TCC PWM solenoid valve ignition voltage and control circuits of the J 44152 . Refer to Testing for Continuity.

Refer to Automatic Transmission Inline 20-Way Connector End View.

Does the resistance measure within the specified range?

10-15 Ω

Go to Step 8

Go to Step 9

8 | Measure the resistance from the TCC PWM solenoid valve control circuit to ground. Refer to Testing for Continuity. Does the resistance measure greater than the specified value? | 250 K Ω | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 10
9 |

1. Disconnect the AT wiring harness 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 Ω

Go to Step 17

Go to Step 18

10 |

1. Disconnect the AT wiring harness 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 Ω

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 for complete circuit distribution. Test the ignition voltage circuit of the TCC PWM solenoid valve for a short to ground between the fuse block underhood and the AT inline 20-way connector. Refer to Testing for Short to Ground and Wiring Repairs.

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 for complete circuit distribution. Test the ignition 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.

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 for complete circuit distribution. Test the ignition voltage circuit of the TCC PWM solenoid valve for an open. Refer to Testing for Continuity and Wiring Repairs.

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 and the AT inline 20-way connector. Refer to Testing for Short to Ground and Wiring Repairs. 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 between the PCM and the AT inline 20-way connector. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | -- | Go to Step 20 | Go to Step 19
17 | Replace the AT wiring harness. 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. 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:

• | 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.

4. Select Specific DTC.
5. Enter DTC P2764.

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 | System OK