P0977
DTC P0756, P0976, or P0977
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0756
- Shift Solenoid B Performance (Shift Solenoid Valve S2)
DTC P0976
- Shift Solenoid B Control Circuit Low (Shift Solenoid Valve S2)
DTC P0977
- Shift Solenoid B Control Circuit High (Shift Solenoid Valve S2)
Diagnostic Fault Information
Circuit/System Description
The powertrain control module (PCM) provides a B+ control circuit to the shift solenoid valve S2. The ground circuit is provided through the body of the shift solenoid. The PCM uses signals from both vehicle speed sensors to detect the actual gear position (1st, 2nd, 3rd or 4th gear). The PCM then compares the actual gear with the shift schedule stored in the PCM memory to detect electrical concerns with the PCM, shift solenoid, electrical circuits or with the mechanical components of the transmission. When the gear position commanded by the PCM and the actual gear positions are not the same, the PCM illuminates the MIL and stores the DTC.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
P0756
The gear position commanded by the PCM and the actual gear position are not the same.
P0982
The PCM detects a short to ground in the voltage circuit of the shift solenoid valve S2.
P0983
The PCM detects an open/high resistance in the voltage circuit of the shift solenoid valve S2.
Action Taken When the DTC Sets
DTC P0756, P0976 or P0977 are type A DTCs.
Conditions for Clearing the DTC
DTC P0756, P0976 or P0977 are type A DTCs.
Diagnostic Aids
* The battery must be fully charged. Refer to Battery Inspection/Test (Battery Inspection/Test).
* All resistance tests are conducted with the component at 20°C (68°F).
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Mechanical Component Description (Mechanical Component Description)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Powertrain Control Module Scan Tool Information (Scan Tool Testing and Procedures)
Circuit/System Verification
Note: If any other DTCs are set, diagnosis them first. Refer to Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle).
1. Operate the vehicle at less than 48 km/h (30 mph) with a steady throttle input.
2. Command the transmission to shift up or shift down with a scan tool. The transmission should shift to the gear commanded by the scan tool.
3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Note: For DTCs P0976 or P0977.
1. Ignition OFF, disconnect the transmission harness connector.
2. Test for 11-15 ohm between the transmission component connector terminal 10 and ground.
• If not within the specified value, test the internal transmission circuits for a short to ground or an open/high resistance. If the circuit tests normal, replace the shift solenoid valve S2.
3. Ignition OFF, connect the transmission harness connector.
4. Disconnect the PCM X2 harness connector.
5. Test for 11-15 ohm between the PCM harness connector X2 terminal 78 and ground.
• If not within the specified value, test the voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PCM.
6. If all circuits test normal, refer to Symptoms - Automatic Transmission (Symptoms - Automatic Transmission).
Component Testing
Note: For DTC P0756.
1. Ignition OFF, remove the shift solenoid valve S2.
2. Connect a 10 A fused jumper wire to the terminal of the shift solenoid S2 and B+.
3. Connect a second jumper wire to the body of the shift solenoid valve S2.
4. Momentary connect the other end of the second jumper wire to B-. The solenoid should energize and make a click sound.
• If the solenoid does not energize and click, replace the shift solenoid valve S2.
5. If all circuits test normal, refer to Symptoms - Automatic Transmission (Symptoms - Automatic Transmission).
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the repair.
* Control Valve Body Replacement (MVB 4 Speed - Automatic Transmission)
* Powertrain Control Module Replacement (Service and Repair)
* Powertrain Control Module Programming and Setup (Testing and Inspection)