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 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.

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

Conditions for Setting the DTC

    • No MAF DTCs P0101, P0102, or P0103 are set.
    • No TP DTCs P0121, P0122, or P0123 are set.
    • No VSS DTCs P0502, or P0503 are set.
    • No A/T ISS DTCs P0716, or P0717 are set.
    • No TCC Stuck ON DTC P0742 is set.
    • No TFP Val. Position Sw. DTC P1810 is set.
    • No TCC PWM Sol. Valve DTC P1860 is set.
    • The engine has been running for more than 5 seconds.
    • The TFP Val. Position Sw. is not indicating Park or Neutral.
    • The TCC Sol. Valve is commanded ON at maximum duty cycle.
    • The throttle angle is greater than 8°.
    • Not in fuel shut off
    • The transmission gear ratio indicates 2nd, 3rd, or 4th gear.
    • The transmission fluid temperature is 20-120°C (68-248°F).
    • Delivered torque is between 43-202 N·m (32-150 lb ft).
    • 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 Torque Converter Clutch.
    • The PCM inhibits 4th gear if the transmission is in hot mode.

Conditions for Clearing the MIL/DTC

    • The PCM turns OFF the MIL after three consecutive ignition cycles 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 chart.

  1. This Step ensures that you perform the Powertrain On-Board Diagnostic System check.

  2. This Step inspects the transmission fluid to ensure that it is at the proper level.

  3. This Step verifies that the TCC engages when commanded ON by the scan tool.

  4. This Step inspects, and repairs if necessary, several components for no TCC engagement.

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 A 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 (tech 1) .
  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. The Clear Info function will erase the data.

  4. Record the DTC Freeze Frame and Failure Records.

Is DTC P0719 set?

--

Go to Step 4

Go to Step 5

4

Inspect and repair the brake switch circuit. 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. On the scan tool, select Output Test.
  3. Select TCC Ena Sol.
  4. Command the TCC Enable Solenoid ON.
  5. Monitor the TCC slip speed display.

Is the slip speed within the specified parameters?

-10 to +67 RPM

Go to Diagnostic Aids

Go to Step 6

6

Inspect and repair the following items:

    • 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 turban shaft seals are worn or cut.
    • The torque converter clutch for ballooning

Refer to Unit Repair.

Is the inspection and repair procedure 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