GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2001 🢒 LeSabre 🢒 Body and Accessories 🢒 Body Control System 🢒 DTC P0741

Object Number: 652020 Size: MF
Master Electrical Component List
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

Circuit Description

The PCM controls the torque converter clutch pulse width modulation (TCC PWM) solenoid valve. The solenoid controls the hydraulic fluid for TCC apply and release. When the TCC is fully applied, the engine is coupled directly to the transmission through the TCC.

The TCC used is an electronically controlled capacity clutch (ECCC). The PCM will normally allow a small amount of slip to occur with the ECCC. When the TCC is engaged, TCC slip speed is maintained at approximately 20 to 50 RPM.

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 Running the DTC
    • No TP sensor DTC P0121, P0122 or P0123.
    • No VSS DTC P0502 or P0503.
    • No AT ISS sensor DTC P0716 or P0717.
    • No TCC stuck ON DTC P0742.
    • No TFP manual valve position switch DTC P1810.
    • No TCC PWM solenoid valve DTC P1860.
    • No TCC release switch DTC P1887.
    • The engine speed is greater than 500 RPM for 5 seconds and not in fuel shut off.
    • The transmission gear range is D4, D3 or D2.
    • The time since the last gear range change is greater than 6 seconds.
    • The transmission fluid temperature is 20-130°C (68-266°F).
    • The TP angle is 4-35%.
    • The TCC PWM solenoid valve is commanded ON for more than 0.5 seconds.
    • The TCC is at maximum apply pressure.

Conditions for Setting the DTC

The following conditions exist for two times during the same ignition cycle:

    • The TCC slip speed is greater than 180 RPM for 7 seconds.
    • The TCC duty cycle is greater than 50 percent.

Action Taken When the DTC Sets
    • The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
    • The PCM inhibits TCC.
    • The PCM inhibits 4th gear if the transmission is in Hot Mode.
    • The PCM freezes shift adapts.
    • The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
    • The PCM stores DTC P0741 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC
    • The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
    • A scan tool can clear the MIL/DTC.
    • The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
    • The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

Test Description

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

  1. This step verifies that the TCC engages when commanded ON by the Scan Tool .

DTC P0741 TCC System Stuck Off

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls in Engine Controls

2

Did you perform the transmission fluid checking procedure?

--

Go to Step 3

Go to Transmission Fluid Check

3
  1. Install a Scan Tool .
  2. Turn ON the ignition with the engine OFF.

    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.

  3. Record the Freeze Frame and Failure Records.
  4. Clear the DTCs.
  5. Start the engine.
  6. With the Scan Tool , observe the TCC Release Pressure parameter.

Does the Scan Tool indicate Yes for the TCC Release Pressure parameter?

--

Go to Step 5

Go to Step 4

4
  1. Inspect the following components:
    2. • The TCC control valve
    • The TCC regulator apply valve
    • The TCC PWM solenoid valve
    • The pressure regulator valve
  2. Repair or replace any malfunctioning components.

    3. Refer to Transmission Overhaul in the 4T65-E Section of the Transmission Unit Repair Manual.

Did you complete the repair?

--

Go to Step 7

--

5

  1. Drive the vehicle above 72 km/h (45 mph) in D3 or D4 with a TP angle of 5-35%.
  2. With the Scan Tool , command the TCC PWM solenoid valve ON and observe the TCC slip speed.

Does the Scan Tool indicate the slip speed is within the specified value?

-50 to +50 RPM

Go to Intermittent Conditions in Engine Controls

Go to Step 6

6
  1. Inspect the following components:
    2. • The cooling system for plugging. The cooling lines may be pinched. Refer to Transmission Fluid Cooler Flushing and Flow Test .
    • The TCC control valve for sticking
    • The TCC regulator valve for sticking
    • The TCC PWM solenoid valve and O-ring seal for leaks
    • The TCC PWM solenoid valve filter for plugging
    • The TCC blowoff valve or spring for damage or not seating.
    • The turbine shaft seals for leaks
    • The torque converter clutch
  2. Repair or replace the component as necessary.

    3. Refer to Transmission Overhaul in the 4T65-E Section of the Transmission Unit Repair Manual.

Did you complete the repair?

--

Go to Step 7

--

7

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Drive the vehicle in D3 or D4 until the TCC is engaged.
    4. • TP angle must be 4-35%.
    • Time since the last range change must be greater than 6 seconds.
    • The TCC is commanded ON at greater than 50 percent duty cycle.
    • TCC slip speed must be less than 50 RPM for at least 4 seconds.
  4. Select Specific DTC.
  5. Enter DTC P0741.

Has the test run and passed?

--

System OK

Go to Step 1