P0976
DTC P0976 or P0977
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) 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
Typical Scan Tool Data
Circuit/System Description
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.
Conditions for Running the DTC
The engine speed is greater than 500 RPM for 2 seconds.
Conditions for Setting the DTC
P0976
The TCM detects an open or short to ground on the 2-3 SS valve control circuit for 4.4 seconds.
P0977
The TCM detects a short to voltage on the 2-3 SS valve control circuit for 4.4 seconds.
Action Taken When the DTC Sets
P0976
* DTC P0976 is a Type A DTC.
* The TCM inhibits 1st and 4th gear.
* The TCM commands maximum line pressure.
* The TCM freezes transmission adaptive functions.
P0977
* DTC P0977 is a Type A DTC.
* The TCM inhibits 4th gear.
* The TCM 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 (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Electronic Component Description (Electronic Component Description) for Shift Solenoid Valves 1-2 and 2-3 information
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
J 44152 Jumper Harness (20 pins)
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 automatic transmission (AT) inline 20-way connector at the transmission.
2. Install the J 44152 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 E 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 E.
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 internal transmission wiring harness assembly and the 2-3 shift solenoid.
Component Testing
1. Ignition OFF, disconnect the automatic transmission (AT) inline 20-way connector at the transmission.
2. Install the J 44152 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 E 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 wiring harness assembly, 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 wiring harness assembly, if the circuits test normal, replace the 2-3 shift solenoid.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the repair.
* 2-3 Shift Solenoid Valve Replacement (2-3 Shift Solenoid Valve Replacement)
* Wiring Harness Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for TCM replacement, setup, and reprogramming