For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptor

DTC P2769: Torque Converter Clutch (TCC) Enable Solenoid Control Circuit Low Voltage
DTC P2770: Torque Converter Clutch (TCC) Enable Solenoid Control Circuit High Voltage

### Circuit/System Description

The torque converter clutch (TCC) solenoid valve is an electrical device that is used with the torque converter clutch pulse width modulation (TCC PWM) solenoid valve in order to control TCC apply and release. The TCC solenoid valve attaches to the transmission case assembly extending into the pump cover. The TCC solenoid valve receives voltage through the ignition voltage circuit. The transmission control module (TCM) controls the solenoid by providing the ground path on the TCC solenoid valve control circuit. The TCM monitors the throttle position (TP) voltage, the vehicle speed and other inputs in order to determine when to energize the TCC solenoid valve.

### Conditions for Running the DTC

#### P2769

• | The system voltage is 8-18 volts.

• | The engine speed is greater than 475 RPM for 5 seconds.

• | Vehicle speed is less than 200 km/h (124 mph).

#### P2770

• | The system voltage is 8-18 volts.

• | The engine speed is greater than 475 RPM for 5 seconds.

• | Vehicle speed is less than 200 km/h (124 mph).

### Conditions for Setting the DTC

#### P2769

The following conditions occurs for 5 seconds:

• | The TCM detects an open in the TCC solenoid valve circuit when the TCC is commanded ON.

• | The TCM detects a short to ground in the TCC shift solenoid valve circuit when the TCC is commanded ON.

#### P2770

The TCM commands the solenoid ON and the voltage feedback remains high, B+.

### Action Taken When the DTC Sets

• | DTCs P2769 and P2770 are Type B DTCs.

• | The TCM inhibits TCC engagement.

• | The TCM commands maximum line pressure.

• | The TCM inhibits 4th gear if in hot mode.

• | The TCM freezes transmission adaptive functions.

### Conditions for Clearing the DTC

DTCs P2769 and P2770 are Type B DTCs.

### Reference Information

#### Schematic Reference

Automatic Transmission Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Transmission General Information

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Transmission Control Module Scan Tool Information

#### Special Tools

• | J 35616 GM-Approved Terminal Test Kit

• | J 44152 Jumper Harness (20 pins)

### Circuit/System Verification

Verify that DTCs P0787, P0973, P0976, P2764 have not set, if so, diagnose first. With a scan tool, command the TCC Solenoid valve ON and OFF.

### Circuit/System Testing

1. Inspect the TRANS fuse for an open.

⇒ | If the fuse is open, test the ignition 1 voltage circuit and the affected control circuit for a short to ground between the Fuse Block-Underhood and the AT inline 20-way connector.

2. Disconnect the AT inline 20-way connector. Connect the J 44152 jumper harness (20 pins), to the engine side of the connector. Using the J 35616 GM-approved terminal test kit, connect a test lamp between the ignition 1 voltage circuit and the affected control circuit. Turn On the ignition with the engine OFF. Using the scan tool output controls command the affected solenoid ON and OFF. The test lamp should blink ON and OFF as commanded.

⇒ | If the test lamp is always OFF, test the circuit for an open.

3. Connect the J 44152 to the transmission side of the connector. Using the J 35616 , measure the resistance between the ignition 1 voltage circuit and the affected control circuit. Resistance should be between 21-33 ohms for the TCC Solenoid valve.

⇒ | If resistance is greater than the specified range, test the circuits for an open. If the resistance is less than the specified range, test for a faulty solenoid or a shorted together condition.

4. Measure the resistance between the ignition 1 voltage circuit and the transmission case. The resistance should be greater than 250K ohms.

⇒ | If the resistance is less than 250K ohms, test the ignition 1 voltage circuit for a short to ground.

5. Measure the resistance between the affected control circuit and ground. The resistance should be greater than 250K ohms.

⇒ | If the resistance is greater than 250K ohms, test the affected control circuit for a short to ground.

### Component Testing

1. Using the J 44152 and the J 35616 , measure the resistance between the ignition 1 voltage circuit and the TCC Solenoid valve circuit. The resistance should be between 21-33 ohms for the TCC Solenoid valve.

⇒ | If the resistance is not within the specified range, remove the affected solenoid.

2. Disconnect the wiring harness connector from the affected solenoid. Measure the resistance of the affected control circuit. The resistance should be between 21-33 ohms for the TCC Solenoid valve.

⇒ | If the resistance is not within the specified range, replace the affected solenoid.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Torque Converter Clutch Pulse Width Modulation Solenoid, Torque Converter Clutch Solenoid, and Wiring Harness

• | Control Module References for replacement, setup and reprogramming.