GM Service Manual Online
For 1990-2009 cars only

Object Number: 25443  Size: SF
Automatic Transmission Components
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

Circuit Description

The Powertrain Control Module (PCM) controls the Torque Converter Clutch Solenoid Valve (TCC Sol. Valve) pulse width modulation (PWM). The solenoid controls the hydraulic fluid for TCC apply and release. When the TCC is applied, the engine is coupled directly to the transmission through the TCC. The TCC slip speed should be near 0.

If the PCM detects high torque converter slip when the TCC is commanded ON, then DTC P0741 sets. DTC P0741 is a Type B DTC.

Conditions for Setting the DTC

    • No MAF DTCs P0101, P0102, or P0103.
    • No TP DTCs P0121, P0122, or P0123.
    • No VSS DTCs P0502, or P0503.
    • No A/T ISS DTCs P0716, or P0717.
    • No TCC Stuck ON DTC P0742.
    • No TFP Val. Position Sw. DTC P1810.
    • No TCC PWM Sol. Valve DTC P1860.
    • The engine has been running for more than 5 seconds.
    • The engine is not in fuel cut off.
    • The TFP Val. Position Sw. indicates D4.
    • The transmission gear ratio indicates 2nd, 3rd, or 4th gear.
    • The throttle angle is greater than 8 degrees.
    • The transmission fluid temperature is -18-130°C (0-266°F).
    • Delivered torque is between 43-202 N·m (32-150 lb ft).
    • The TCC Sol. Valve is commanded ON at maximum duty cycle.
    • The TCC slip must not exceed torque limits.

Action Taken When the DTC Sets

    • The PCM illuminates the Malfunction Indicator Lamp (MIL).
    • SERVICE ENGINE SOON, SERVICE TRANSMISSION displays on the Driver Information Center (DIC).
    • The PCM inhibits TCC engagement.
    • The PCM inhibits 4th gear if the transmission is in hot mode.
    • DTC P0741 is stored in the PCM history.

Conditions for Clearing the MIL/DTC

    • The PCM turns OFF the MIL after three consecutive trips without a failure reported.
    • A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.
    • The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

Diagnostic Aids

    • Inspect the transmission fluid level.
    • The transmission may be in hot mode. Inspect the transmission fluid lines to the radiator. The lines may be pinched, plugged or twisted.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step inspects the transmission fluid to ensure that it is at the proper level.

  2. This step verifies that the TCC engages when commanded ON by the scan tool.

DTC P0741 Torque Converter Clutch System Stuck OFF

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Have you performed the transmission fluid checking procedure?

--

Go to Step 3

Go to Transmission Fluid Check

3

  1. Install the Scan Tool .
  2. With the engine OFF, turn the ignition switch to the RUN position.
  3. Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM.

  4. Record the DTC Freeze Frame and Failure Records, then clear the DTCs.

Is DTC P0719 set?

--

Go to Step 4

Go to Step 5

4

  1. Inspect the brake switch circuit.
  2. Repair the circuit if necessary.

Refer to DTC P0719 Brake Switch Circuit Low Input .

Is the repair complete?

--

Go to Step 7

--

5

  1. Drive the vehicle at 72 km/h (45 mph).
  2. Using the scan tool, command the TCC PWM Sol. Valve ON and monitor the TCC slip speed display.

Is the slip speed within the specified parameters?

-5 to +80 RPM

Go to Diagnostic Aids

Go to Step 6

6

  1. Inspect for the following conditions:
  2. • The TCC control valve is stuck OFF due to sediment or binding.
    • The TCC regulator valve is stuck OFF due to sediment or binding.
    • The TCC feed valve is stuck OFF due to sediment or binding.
    • The oil pressure screen is clogged.
    • The TCC Sol. Valve O-ring is leaking or cut.
    • The turbine shaft seals are worn or cut.
    • The torque converter for ballooning.
  3. Repair or replace any malfunctioning component.

Refer to Unit Repair.

Is the inspection and repair complete?

--

Go to Step 7

--

7

In order to verify your repair, perform the following procedure:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
  4. 3.1. Road test the vehicle with the gear select lever in D4.
    3.2. Ensure the TCC applies for more than 5 seconds.
  5. Select Specific DTC. Enter DTC P0741.

Has the test run and passed?

--

System OK

Begin the diagnosis again. Go to Step 1