GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 Regal 🢒 DTC 🢒 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 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 and is not serviced separately. 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

For equivalent regional tools, refer to Special Tools.

Circuit/System Verification
  1. Perform the Transmission Fluid Check to verify correct fluid level and condition. The transmission fluid level should be within the crosshatch band and the transmission fluid should be red or dark brown.
    2. ⇒If the transmission fluid is low or discolored, refer to Transmission Fluid Replacement.
  2. Engine idling at operating temperature. Attempt to clean or free up a potential sticking valve with the scan tool Service Cleaning Procedure. Refer to Control Solenoid Valve and Transmission Control Module Assembly Cleaning for further instructions.
  3. 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. The DTCs should not set.
  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.

Circuit/System Testing
  1. Ignition OFF, remove the control solenoid (w/body and TCM) valve assembly.
  2. Install the DT-48616 plate to the control solenoid (w/body and TCM) valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test for detailed instructions.
  3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test. A pressure change should occur.
    4. ⇒If a pressure change does not occur, replace the control solenoid (w/body and TCM) valve assembly.
  4. Inspect for the following conditions and repair/replace as necessary:
    5. • Lower control valve body for a stuck valve, debris or damage
    • TCC control valve in the pump for a stuck valve, debris or damage
    • Torque converter assembly for damage or discoloration

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

       Note: 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.