6L80-E Automatic Transmission

DTC P0741 or P0742

DTC Descriptor
This diagnostic procedure supports the following DTCs:
^ DTC P0741 Torque Converter Clutch (TCC) - Stuck Off
^ DTC P0742 Torque Converter Clutch (TCC) - Stuck On

Circuit/System Description
The torque converter clutch (TCC) pressure control (PC) solenoid is part of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The shift solenoid (SS) 1 supplies transmission fluid to the TCC PC solenoid when commanded OFF. The TCC PC solenoid regulates transmission fluid through the TCC regulator valve in the lower valve body and the TCC control valve in the pump, to the TCC when commanded ON and exhausts fluid when commanded OFF. When the TCC is applied, the engine is coupled directly to the transmission.

Conditions for Running the DTC
^ No DTCs P0716 or P0717.
^ No DTCs P0722 or P0723.
^ No DTCs P2762, P2763, or P2764.
^ No DTCs P0741 or P0742.
^ The engine run time is greater than 5 seconds.
^ The transmission fluid temperature (TFT) is 20 - 130°C (68 - 266°F).
^ The calculated throttle position is between 8-90%.
^ The engine torque is greater than 50 Nm (36 ft. lbs.).
^ The 2nd gear ratio is between 1.42-1.63.
^ The 4th gear ratio is between 1.06-1.23.
^ The 5th gear is between 0.79-0.90.
^ The 6th gear is between 0.62-0.71.
^ The TCC is commanded ON and PWM duty cycle is greater than 60% for 5 seconds.

Conditions for Setting the DTC

DTC P0741
The TCM detects TCC slip greater than 125 RPM for 5 seconds when the TCC is commanded ON. This must occur 4 times.

DTC P0742
The TCM detects the TCC slip between -20 and 40 RPM for 4 seconds when the TCC is commanded OFF. This must occur 3 times.

Action Taken When the DTC Sets
^ DTCs P0741 and P0742 are Type B DTCs.
^ Inhibit high gear in Hot Mode.
^ The TCM inhibits TCC.
^ The TCM freezes transmission adaptive functions.

Conditions for Clearing the DIC/DTC
DTCs P0741 and P0742 are Type B DTCs.

Diagnostic Aids
When attempting to set transmission performance DTCs, it may be helpful to observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. Ensure the transmission fluid level is correct and there are no leaks.

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

^ Special Tools Required
- DT 47825-1?

Circuit/System Verification
1. Perform the transmission fluid checking procedure. Refer to Transmission Fluid Checking Procedure. Procedures
2. Operate the vehicle in drive with the calculated throttle position greater than 8% and ensure TCC is commanded ON and OFF a minimum of 5 times. If the DTC resets, go to Component Testing.

Component Testing
1. Perform the control solenoid (w/body and TCM) valve assembly cleaning procedure in an attempt to clean or free up a potential sticking valve of dirt or debris. Refer to Control Solenoid Valve and Transmission Control Module Assembly Cleaning. Control Solenoid Valve & TCM Assembly Cleaning If the DTC resets after the cleaning procedure perform the control solenoid (w/body and TCM) valve assembly inspection procedure.
2. Perform the control solenoid (w/body and TCM) valve assembly solenoid performance test to test for a stuck open or stuck closed TCC PC Solenoid valve inside of the control solenoid (w/body and TCM) valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test. Control Solenoid Valve & TCM Assembly Solenoid Performance Test If a stuck open or closed valve is found, replace the control solenoid (w/body and TCM) valve assembly.
3. Inspect the lower control valve body for a stuck valve, debris or damage. If you found a valve body concern, repair or replace the lower control valve body as necessary.
4. Inspect the TCC control valve in the pump. If you found a TCC control valve concern, repair or replace the TCC control valve or pump as necessary.
5. Inspect the torque converter assembly for damage or discoloration. If you found a torque converter assembly concern, replace the torque converter assembly as necessary.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
^ Control valve body replacement: Refer to Control Valve Body Disassemble.
^ Torque converter replacement: Refer to Torque Converter Replacement.
^ Control solenoid (w/body and TCM) valve assembly replacement: Refer to Control Module References for replacement, setup, and programming and Diagnostic System Check - Vehicle. Programming and Relearning
^ Transmission pump repair or replacement: Refer to Pump Repair in the Transmission.