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 Descriptors

DTC P0976 : 2-3 Shift Solenoid (SS) Control Circuit Low Voltage
DTC P0977: 2-3 Shift Solenoid (SS) Control Circuit High 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

### Circuit/System Description

The 1-2 shift solenoid (SS) valve controls the fluid flow acting on the 1-2 and 3-4 shift valves. The solenoid is a normally-open exhaust valve. With the 2-3 SS valve, the 1-2 SS valve allows 4 different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 1-2 SS valve receives ignition voltage through the ignition voltage circuit. The transmission control module (TCM) controls the solenoid by providing the ground path on the 1-2 SS valve control circuit.

### Conditions for Running the DTC

• | The engine speed is 500 RPM for 5 seconds.

• | The 2-3 SS is commanded ON.

### Conditions for Setting the DTC

#### P0976

• | The TCM detects an open in the 2-3 shift solenoid valve circuit when commanded ON.

• | The TCM detects a short to ground in the 2-3 shift solenoid valve circuit when commanded ON.

#### P0977

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

### Action Taken When the DTC Sets

#### P0976

• | P0976 is a Type A DTC.

• | The TCM inhibits 1st and 4th gear.

• | The TCC commands maximum line pressure.

• | The TCM freezes transmission adaptive functions.

#### P0977

• | P0977 is a Type A DTC.

• | The TCM inhibits 4th gear.

• | The TCC commands maximum line pressure.

• | The TCM freezes transmission adaptive functions.

### Conditions for Clearing the DTC

DTCs P0976 and P0977 are Type A 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 44152 Jumper Harness (20 Pins)

• | J 45681 Jumper Harness

### Circuit/System Verification

1. Ignition ON, engine OFF, observe the 2-3 Sol. CKT Status parameter while commanding the 2-3 SS ON and OFF with a scan tool. The reading should display OK or Indeterminate.
2. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

Important: Additional DTCs may set when disconnecting the automatic transmission inline 20-way connector.

1. Ignition OFF, disconnect the AT inline 20-way connector at the transmission.
2. Install the J 45681 jumper harness, on the engine side of the AT inline 20-way connector.
3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal L and ground.

⇒ | 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 ignition circuit fuse is open, test all components connected to the ignition circuit and replace as necessary.

4. Connect a test lamp between the control circuit terminal B and the ignition circuit terminal L.
5. Command the 2-3 SS ON and OFF with a scan tool. The test lamp should turn ON and OFF 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.

6. If all circuits test normal, test the automatic transmission internal wiring harness and the 2-3 shift solenoid.

### Component Testing

1. Ignition OFF, disconnect the AT inline 20-way connector at the transmission.
2. Install the J 44152 jumper harness (20 pins), on the transmission side of the AT inline 20-way connector.
3. Test for 19-31 ohms of resistance between the control terminal B and the ignition terminal L of the transmission.

⇒ | If not within the specified range, test the circuits for a short to ground or an open/high resistance. If a circuit is shorted or open replace the internal transmission harness, if the circuits test normal, replace the 2-3 shift solenoid.

4. Test for infinite resistance between each terminal and the transmission housing/case.

⇒ | If not the specified value, test the circuits for a short to ground or an open/high resistance. If a circuit is shorted replace the internal transmission harness, if the circuits test normal, replace the 2-3 shift solenoid.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• | Control and Shift Solenoids Replacement

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

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