Diagnostic Instructions

DTC Descriptors

DTC P0973 : 1-2 Shift Solenoid (SS) Control Circuit Low Voltage

DTC P0974: 1-2 Shift Solenoid (SS) Control Circuit High Voltage

DTC P0976: 2-3 Shift Solenoid (SS) Control Circuit Low Voltage

DTC P0977: 2-3 Shift Solenoid (SS) Control Circuit High Voltage

DTC P2763: Torque Converter Clutch (TCC) Pressure Control (PC) Solenoid Control Circuit High Voltage

DTC P2764: Torque Converter Clutch (TCC) Pressure Control (PC) Solenoid Control Circuit Low Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
Ignition 1 Voltage	P0973, P0976, P2764	P0973, P0976, P2764	--
1-2 SS Valve Control	P0973	P0973	P0974
2-3 SS Valve Control	P0976	P0976	P0977
TCC PWM Valve Control	P2764	P2764	P2763

Typical Scan Tool Data

1-2, 2-3 and Torque Converter Clutch Pressure Control Solenoid

Circuit	Normal	Short to Ground	Open/High Resistance	Short to Voltage
Operating Conditions: Engine running, normal operating temperature Parameter Normal Range: Indeterminate
1-2 Sol. CKT Status	Indeterminate	Short to GND	Open	Short to Volts
2-3 Sol. CKT Status	Indeterminate	Short to GND	Open	Short to Volts
TCC Duty Cycle CKT Status	Indeterminate	Short to GND	Open	Short to Volts

Circuit/System Description

The 1-2 Shift and 2-3 Shift Solenoids

The 1-2 shift solenoid (SS) valve and the 2-3 SS valves control transmission fluid pressure acting on the shift valves to position the valves for the appropriate gear. The 1-2 SS and the 2-3 SS valves are normally-open exhaust valves located on the control valve body. A fused circuit supplies ignition voltage to the 1-2 SS valve and the 2-3 SS valve. The transmission control module (TCM) commands the solenoid ON or OFF by switching the ground path. When the 1-2 SS valve or the 2-3 SS valve is commanded ON, the TCM senses low voltage. When the 1-2 SS valve or the 2-3 SS valve is commanded OFF, the TCM senses high voltage.

Torque Converter Clutch (TCC) Solenoid

The torque converter clutch (TCC) pulse width modulated (PWM) solenoid is a normally closed solenoid used to control the apply and release of the converter clutch. When the vehicle operating conditions are appropriate to apply the TCC, the transmission control module (TCM) immediately increases the duty cycle to approximately 42 percent. The TCM then ramps the duty cycle to approximately 90 percent to achieve full TCC apply pressure. When the TCC is fully applied, the engine is coupled directly to the transmission through the TCC. When the solenoid is commanded OFF, the TCM senses high voltage. When the solenoid is commanded ON, the TCM senses low voltage.

Conditions for Running the DTC

P0973, P0974, P0976 and P0977

P2763

P2764

Conditions for Setting the DTC

P0973 and P0976

The TCM detects an open or short to ground on the shift solenoid valve control circuit for 4.4 seconds.

P0974 and P0977

The TCM detects a short to voltage on the shift solenoid valve control circuit for 4.4 seconds.

P2763

The TCM detects a short to voltage on the TCC PWM solenoid control circuit for 4.4 seconds.

P2764

The TCM detects an open or short to ground on the TCC PWM solenoid control circuit for 4.4 seconds.

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References

Special Tools

Circuit/System Verification

Start and idle the engine. Using the scan tool output controls command the affected solenoid ON and OFF. Observing the CKT Status parameter on the scan tool, ensure the parameter shows OK.

Circuit/System Testing

1. Ignition OFF, disconnect the transmission 20-way harness connector.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal and ground.

•	Terminal E for shift solenoid valve 1-2 and 2-3.

•	Terminal U for the TCC solenoid.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the fuse is open, test or replace the affected solenoid.

3. Connect a test lamp between the control circuit terminal and the ignition voltage circuit terminal.

•	Terminals E and A for shift solenoid valve 1-2.

•	Terminals E and B for shift solenoid valve 2-3.

•	Terminals U and T for the TCC solenoid.

4. Command the affected shift solenoid ON and OFF with a scan tool or command the TCC solenoid to 90 percent with a scan tool. The test lamp should respond when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the TCM.

⇒	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the TCM.

5. If all circuits test normal, test or replace the internal transmission wiring harness or the affected solenoid.

Component Testing

Shift Solenoid Valves

1. Ignition OFF, disconnect the transmission harness connector.
2. Test for 19-24 ohms of resistance at 20°C (68°F) or 24-31 ohms of resistance at 88°C (188°F) between the ignition voltage terminal and the control terminal of the affected shift solenoid valve.

•	Terminals E and A for shift solenoid valve 1-2.

•	Terminals E and B for shift solenoid valve 2-3.

⇒	If not within the specified range, test the internal transmission wiring harness for an open or high resistance. If the circuits test normal, replace the affected shift solenoid valve.

3. Test for infinite resistance between each terminal and ground.

⇒	If not the specified value, test the internal transmission wiring harness for a short to ground. If the circuits test normal, replace the affected shift solenoid valve.

TCC Solenoid

1. Ignition OFF, disconnect the transmission harness connector.
2. Test for 10-12 ohms of resistance at 20°C (68°F) or 13-15 ohms of resistance at 88°C (188°F) between the ignition voltage terminal U and the control terminal T of the TCC solenoid.

⇒	If not within the specified range, test the internal transmission wiring harness for an open or high resistance. If the circuits test normal, replace the TCC solenoid.

3. Test for infinite resistance between each terminal and ground.

⇒	If not the specified value, test the internal transmission wiring harness for a short to ground. If the circuits test normal, replace the TCC solenoid valve.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.