6L80-E Automatic Transmission
DTC P0973 or P0974
DTC Descriptor
This diagnostic procedure supports the following DTCs:
^ DTC P0973 Shift Solenoid (SS) 1 Control Circuit Low Voltage
^ DTC P0974 Shift Solenoid (SS) 1 Control Circuit High Voltage
Diagnostic Fault Information
Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
Typical Scan Tool Data
Circuit/System Description
The shift solenoid (SS) 1 is part of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The control solenoid (w/body and TCM) valve assembly supplies 12 volts to SS 1 on the high side driver 2 circuit. The control solenoid (w/body and TCM) valve assembly controls the normally closed SS 1 on the SS 1 control circuit. The SS 1 controls the transmission fluid to the Mode-2 valve. In the OFF position no oil is supplied to the clutch pressure control (PC) solenoid 3 or the transmission fluid pressure (TFP) switch 5, and the 4-5-6 clutch is fed by drive fluid. In the ON position, Reverse fluid is allowed to flow and is supplied to the 3-5-R clutch.
Conditions for Running the DTC
^ The engine run time is greater than 5 seconds.
^ The SS 1 is commanded ON or OFF.
Conditions for Setting the DTC
DTC P0973
The control solenoid (w/body and TCM) valve assembly detects an internal low voltage electrical malfunction of the SS 1 control circuit when the SS 1 is commanded OFF for 300 milliseconds.
DTC P0974
The control solenoid (w/body and TCM) valve assembly detects an internal high voltage electrical malfunction of the SS 1 control circuit when the SS 1 is commanded ON for 300 milliseconds.
Action Taken When the DTC Sets
^ DTCs P0973 and P0974 are Type A DTCs.
^ The TCM defaults the transmission to 3rd gear if the current gear is 1st, 2nd, or 3rd, or 5th gear if the current gear is 4th, 5th, or 5th gear.
^ The TCM inhibits TCC.
^ The TCM commands maximum line pressure.
^ The TCM freezes transmission adaptive functions.
Conditions for Clearing the DIC/DTC
DTCs P0973 and P0974 are Type A DTCs.
Diagnostic Aids
When attempting to set solenoid electrical DTCs, it may be helpful to ensure the control solenoid (w/body and TCM) valve assembly is warmed up and the transmission is operated in 2nd gear long enough to ensure a 3°C (5°F) increase in TCM temperature. This will place the TCM under the optimal conditions to test solenoid electrical DTCs.
Reference Information
Schematic Reference
Connector End View Reference
^ Automatic Transmission Inline 16-Way Connector End View
^ Automatic Transmission Internal Connector End Views
DTC Type Reference
^ Diagnostic Trouble Code (DTC) Type Definitions
^ Diagnostic Trouble Code (DTC) List/Type
Electrical Information Reference
^ Circuit Testing
^ Connector Repairs
^ Testing for Intermittent Conditions and Poor Connections
^ Wiring Repairs
Scan Tool Reference
^ Scan Tool Output Controls
^ Scan Tool Data List
^ Scan Tool Data Definitions
Circuit/System Testing
1. Ensure the transmission fluid temperature is between 50 - 80°C (122 - 176°F).
2. Operate the vehicle in 2nd gear long enough to ensure at least a 3°C (5°F) rise in TCM temperature.
3. Place the gear selector in Reverse for 5 seconds and then idle vehicle for 5 seconds.
4. Observe the scan tool data parameter Shift Sol. 1 CKT Status. The parameter should display OK.
5. If the parameter displays Open, Short to Volts, Short to GND, or if the DTC resets, perform the control solenoid (w/body and TCM) valve assembly inspection procedure.
6. If no concerns are found during the inspection, replace the control solenoid (w/body and TCM) valve assembly.
Repair Instructions
Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests