GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2008 🢒 G8 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P0741 or P0742

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

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 percent.
    • The engine torque is greater than 50 N·m (36 lb. ft).
    • 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 the pulse width modulation (PWM) duty cycle is greater than 60% for 5 seconds.

Conditions for Setting the 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.

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, 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

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing.
    •  Connector Repairs.
    •  Testing for Intermittent Conditions and Poor Connections.
    •  Wiring Repairs.

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. Perform the Transmission Fluid Check.
  2. Operate the vehicle in drive with the calculated throttle position greater than 8 percent and make sure TCC is commanded ON and OFF a minimum of 5 times.
    3. ⇒If the DTC resets, go to Component Testing.

Component Testing
  1. Perform the Control Solenoid Valve and Transmission Control Module Assembly Cleaning in an attempt to clean or free up a potential sticking valve of dirt or debris.
    2. ⇒If the DTC resets after the cleaning procedure perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection.
  2. Perform the Control Solenoid Valve and Transmission Control Module 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.
    3. ⇒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.
    4. ⇒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.
    5. ⇒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.
    6. ⇒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.

    • Control valve body replacement: Refer to Control Valve Lower Body and Upper Body Replacement.
    • Perform the Torque Converter Replacement.
    • Control solenoid (w/body and TCM) valve assembly replacement: Refer to Control Module References for replacement, setup, and programming.
    • Transmission pump repair or replacement: Refer to Torque Converter Housing with Fluid Pump Removal and Torque Converter Housing with Fluid Pump Installation in the Transmission Unit Repair Manual.
    • Perform the Service Fast Learn Adapts.