6T70/6T75 - Automatic Transmission
DTC P0973 or P0974
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 P0973
- Shift Solenoid (SS) 1 Control Circuit Low Voltage
DTC P0974
- Shift Solenoid (SS) 1 Control Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
The shift solenoid (SS) 1 is part of the control solenoid valve assembly, which has no serviceable components. SS 1 is a normally closed (NC) ON/OFF solenoid and is controlled by the TCM through a low side driver. When the SS 1 is energized (ON), SS 1 fluid pressure is directed to the clutch select valve 2, which allows the valve to overcome the spring pressure and move to the applied position. Power to the SS 1 is supplied by the TCM through a high side driver (HSD). The HSD protects the circuit and components from excessive current flow. If excessive current flow is detected, the HSD will turn OFF. When the fault is corrected, the HSD will reset.
Conditions for Running the DTC
P0973
* The engine speed is greater than 400 RPM for 5 seconds.
* The ignition voltage is 8.6 volts or greater.
* DTC P0973 has not set this ignition cycle.
P0974
* The engine speed is greater than 400 RPM for 5 seconds.
* The ignition voltage is 8.6 volts or greater.
* DTC P0974 has not set this ignition cycle.
Conditions for Setting the DTC
P0973
The control solenoid valve assembly detects a short to ground on the SS 1 control circuit for 2 seconds.
P0974
The control solenoid valve assembly detects an open or a short to power on the SS 1 control circuit for 2 seconds.
Action Taken When the DTC Sets
P0973
* DTC P0973 is a Type A DTC.
* The TCM limits the transmission to reverse and 5th gear.
* The TCM inhibits torque converter clutch (TCC) engagement.
* The TCM commands maximum line pressure.
* The TCM freezes transmission adaptive functions.
* The TCM inhibits Tap Up/Down function.
* The TCM inhibits manual shifting of forward gears.
P0974
* DTC P0974 is a Type B DTC.
* The TCM inhibits 1st gear.
Conditions for Clearing the DIC/DTC
* DTC P0973 is a Type A DTC.
* DTC P0974 is a Type B DTC.
Reference Information
Connector End View Reference
* Component Connector End Views (Connector End Views By Name)
* Inline Harness Connector End Views (Connector End Views By Number)
Description and Operation
Transmission General Description (Transmission General 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
Control Module References (Programming and Relearning) for scan tool information
Special Tools
DT-47825-20 Adapter Harness
Circuit/System Verification
1. Operate the vehicle in second gear long enough to ensure at least a 3°C (5°F) rise in TCM temperature, then operate the vehicle in Park for 5 seconds.
2. Place the gear selector in Reverse for 5 seconds and then idle the vehicle in Park for 5 seconds. Verify with a scan tool the following test status parameters display OK:
* Shift Sol. 1 Ctrl. Ckt. High Voltage Test Status
* Shift Sol. 1 Ctrl. Ckt. Open Test Status
* Shift Sol. 1 Ctrl. Ckt. Low Voltage Test Status
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: You must perform the Circuit/System Verification first.
1. Ignition OFF, remove the control solenoid valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Replacement (6T70/6T75 - Automatic Transmission).
2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (Control Solenoid Valve and Transmission Control Module Assembly Inspection).
3. Place the control solenoid valve assembly on a clean work surface near the transmission assembly.
4. Connect DT-47825-20 - jumper harness between the vehicle wire harness electrical connector, and the control solenoid valve assembly electrical connector.
5. Ignition ON, verify with a scan tool the following test status parameters display OK:
* Shift Sol. 1 Ctrl. Ckt. High Voltage Test Status
* Shift Sol. 1 Ctrl. Ckt. Open Test Status
* Shift Sol. 1 Ctrl. Ckt. Low Voltage Test Status
• If any test status parameter displays Fault or Malfunction, replace the control solenoid valve assembly.
Repair Instructions
Important:
* Perform the Service Fast Learn Adapts (6T70/6T75 - Automatic Transmission) following all transmission related repairs.
* Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (Control Solenoid Valve and Transmission Control Module Assembly Inspection).
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Control Module References (Programming and Relearning) for control solenoid valve assembly replacement, setup, and programming