GM Service Manual Online
For 1990-2009 cars only

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 Descriptors

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. The control solenoid (w/body and TCM) valve assembly has no seviceable parts. The TCC PC solenoid is a normally low pressure control solenoid. The actuator feed limit (AFL) valve supplies transmission fluid to the TCC PC solenoid. The TCC PC solenoid supplies transmission fluid to the TCC regulator valve in the lower valve body and the TCC control valve in the pump. When conditions are correct to apply the converter clutch, the TCM will increase TCC PC current flow (duty cycle) thereby increasing pressure to move the TCC control valve into the apply position. When the TCC is fully applied, the engine is coupled directly to the transmission. TCC release is accomplished by the TCM decreasing current flow, dropping the apply pressure thereby allowing the TCC control valve to move to the release position.

Conditions for Running the DTC

P0741

    • No DTCs P0716 or P0717.
    • No DTCs P0722 or P0723.
    • No DTC P0742.
    • No DTCs P2762, P2763, or P2764.
    • The engine run time is greater than 5 seconds.
    • The ignition voltage is between 9.0 volts and 19.0 volts.
    • The transmission fluid temperature (TFT) is 20-130°C (68-266°F).
    • The calc. throttle position is greater than 8 percent.
    • The engine torque is greater than 50 N·m (36 lb ft).
    • The 2nd gear ratio is between 2.75-3.17.
    • The 3rd gear ratio is between 1.78-2.04.
    • The 4th gear ratio is between 1.35-1.55.
    • The 5th gear is between 0.93-1.07.
    • The 6th gear is between 0.70-0.80.
    • The TCC is commanded ON.

P0742

    • No DTCs P0716 or P0717.
    • No DTCs P0722 or P0723.
    • No DTC P0741.
    • No DTC P1751.
    • No DTCs P2762, P2763, or P2764.
    • The engine run time is greater than 5 seconds.
    • The ignition voltage is between 9.0 volts and 19.0 volts.
    • The transmission fluid temperature (TFT) is 20-130°C (68-266°F).
    • The calc. throttle position is greater than 8 percent.
    • The engine torque is greater than 80 N·m (59 lb ft).
    • Vehicle speed greater than 16 km/h (10 mph).
    • Commanded gear is 2nd or greater.
    • The gear ratio is between 0.69-1.97.
    • Solenoid A is enabled.

Conditions for Setting the DTC

P0741

The TCM detects TCC slip greater than 150 RPM for 3 seconds when the TCC is commanded ON 4 times during the same ignition cycle.

P0742

The TCM detects the TCC slip between -20 and 30 RPM for 5 seconds or greater when the TCC is commanded OFF. The vehicle speed is greater than 16 km/h (10 mph) and the commanded gear is 2nd or higher for 6 times during the same ignition cycle.

Action Taken When the DTC Sets

    • DTCs P0741 and P0742 are Type A 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 A 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

Description and Operation

    •  Transmission General Description
    •  Transmission Component and System Description
    •  Electronic Component Description

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

Special Tools

    • DT-48616 Control Solenoid Test Plate
    • DT-48616-10 Adapter Harness

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 ensure TCC is commanded ON and OFF a minimum of 6 times.
  3. If the DTC resets, go to Component Testing.
  4. 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.

Component Testing

    Important: You must perform the Circuit/System Verification before proceeding with 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 .
  3. 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.
  4. If a stuck open or closed valve is found, replace the control solenoid (w/body and TCM) valve assembly.
  5. Inspect the lower control valve body for a stuck valve, debris or damage.
  6. If you found a valve body concern, repair or replace the lower control valve body as necessary.
  7. Inspect the TCC control valve in the pump.
  8. If you found a TCC control valve concern, repair or replace the TCC control valve or pump as necessary.
  9. Inspect the torque converter assembly for damage or discoloration.
  10. If you found a torque converter assembly concern, replace the torque converter assembly as necessary.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

       Important: Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection .

    • Refer to Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming.
    • Perform the Service Fast Learn Adapts following all transmission related repairs.
    • Perform the Torque Converter Removal and the Torque Converter Installation .
    • Perform the:
       -  Control Valve Body Assembly Removal
       -  Control Valve Body Assembly Disassemble
       -  Control Valve Body Cleaning and Inspection
       -  Control Valve Channel Plate Cleaning and Inspection
       -  Control Valve Body Assembly Assemble
       -  Control Valve Body Assembly Installation
    • Perform the:
       -  Torque Converter Housing with Fluid Pump Assembly Removal
       -  Transmission Fluid Pump Disassemble
       -  Transmission Fluid Pump Assemble
       -  Torque Converter Housing with Fluid Pump Assembly Installation