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For 1990-2009 cars only
Makes 🢒 Holden 🢒 2005 🢒 Commodore Executive 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 4L60-E/4L65-E 🢒 DTC P0742

DTC P0742 V6

DTC Description

This diagnostic procedure supports DTC P0742 Torque Converter Clutch (TCC) System -- Stuck On.

Circuit Description

The torque converter clutch (TCC) solenoid valve is a normally-open exhaust valve that is used with the torque converter clutch pulse width modulation (TCC PWM) solenoid valve in order to control fluid acting on the converter clutch apply valve. The TCC solenoid valve attaches to the transmission case assembly extending into the pump cover. When grounded by the transmission control module (TCM), the TCC solenoid valve stops converter signal oil from exhausting. This causes converter signal oil pressure to increase and move the converter clutch apply valve against spring force and into the apply position. In this position, release fluid is open to an exhaust port and converter feed fluid fills the apply fluid circuit. The converter feed fluid applies the TCC. When the TCM no longer provides a ground path, the TCC solenoid valve de-energizes and apply fluid exhausts, releasing the TCC.

When the TCM detects low torque converter slip when the TCC is recommended off, then DTC P0742 sets. DTC P0742 is a type B DTC.

Refer to Automatic Transmission Controls Schematics , Automatic Transmission Inline 20-Way Connector End View , Automatic Transmission Internal Connector End Views , Automatic Transmission Control Module Connector End Views , and Automatic Transmission Related Connector End Views to aid in diagnosis.

Conditions for Running the DTC
    • No DTCs P0722, P0723, P0741, P02763, P02764, P02769 or P02770.
    • Ignition voltage is 8-18 V.
    • The engine run time is greater than 5 seconds.
    • The IMS range is D4.
    • The transmission fluid temperature is 10-130°C.
    • The engine speed is 500-6,500 RPM for 5 seconds, then 800-4,400 RPM
    • The engine torque is 156-881 N·m.
    • The throttle position is greater than 10 percent.
    • The transmission is not in 1st gear and the gear ratio is 0.95:1-1.56:1.
    • The vehicle speed is greater than 15 km/h.
    • TCC is commanded off.

Conditions for Setting the DTC

The following conditions occur four times in one ignition cycle:

    • The TCM commands the TCC off.
    • The TCC slip is -15 +15 RPM for greater than 3 seconds.

Action Taken When the DTC Sets
    • The TCM requests the ECM to illuminate the check powertrain icon during the second consecutive drive trip in which the conditions for setting the DTC are met.
    • The TCM commands maximum line pressure.
    • The TCM freezes transmission adaptive functions.
    • At the time of the first failure, the TCM records the operating conditions when the conditions for setting the DTC are met. The TCM stores this information as a Failure Record.
    • At the time of the second failure, the ECM records the operating conditions when the conditions for setting the DTC are met. The ECM stores this information as a Freeze Frame.
    • The TCM stores DTC P0742 in TCM history.

Conditions for Clearing the DTC
    • The ECM turns off the check powertrain icon after the sixth consecutive drive trip in which the TCM does not send a check powertrain icon illumination request.
    • Tech 2 can clear the DTC.
    • The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
    • The TCM cancels the default actions when the ignition is off long enough in order to power down the TCM.

Diagnostic Aids

The TCC fluid hydraulically applies the TCC, possibly causing an engine stall, under the following conditions:

    • The TCC is hydraulically stuck in the on position
    • The parking brake is applied.
    • Any gear range is selected.
    • Contamination may cause the TCC apply valve to intermittently stick in the valve body.
    • Internal damage in the torque converter may cause no TCC apply.

Test Description

The following numbers refer to the step numbers on the diagnostic table:

2 This step tests the hydraulic state of the TCC. When the TCM commands the TCC solenoid valve off, the slip speed should increase.

3 Checks the mechanical components that cause the DTC and their state.

Step

Action

Yes

No

1

Has the Diagnostic System Check been performed?

Go to Step 2

Refer to Diagnostic System Check - Automatic Transmission

2
  1. Connect Tech 2 to the DLC.
  2. Turn on the ignition, with the engine off.

    3. Important: Before clearing the DTC, use the Tech 2 Freeze Frame/Failure Record in order to record the transmission parameters at the time the DTC set. Using Tech 2 to clear the DTC(s) erases the Freeze Frame/Failure Record records from the TCM.

  3. On Tech 2 select:

    4. Transmission / Automatic Transmission / Diagnostic Trouble Codes / Freeze Frame.

  4. Select the relevant DTC and note the parameters at the time of the DTC setting.
  5. On Tech 2 select:

    6. Diagnostic Trouble Codes / Clear Engine and Transmission DTCs.

  6. Follow the instructions on Tech 2 and clear the DTCs.
  7. On Tech 2 select:

    8. Automatic Transmission / Data Display/ Transmission Data.

  8. Drive the vehicle in the D4 range in second, third, or fourth gear under steady acceleration, with a TP angle at 10%.

On Tech 2, while TCC Solenoid status is On, is the TCC Slip Speed within -20 +20 RPM?

Go to Speed 3

Refer to Diagnostic Aids within this Section

3

The TCC is hydraulically stuck ON. Inspect for the following:

    • Blocked exhaust orifice in the TCC solenoid valve.
    • Converter clutch apply valve stuck in the apply position.
    • Incorrectly aligned or damaged valve body gasket.
    • Restricted release passage.
    • Restricted transmission cooler line.

Did you find and correct the condition?

Go to Step 4

--

4

Perform the following procedure in order to verify the repair:

  1. On Tech 2 select:

    2. Diagnostic Trouble Codes / Clear Engine and & Transmission DTCs.

  2. Follow the instructions on Tech 2 and clear any DTCs.
  3. On Tech 2 select:

    4. Automatic Transmission / Data Display / Transmission Data.

  4. Drive the vehicle in D4 with the TCC ON and the throttle above 10%. Ensure Tech 2 displays TCC Slip Speed between 100-2,500 RPM for 3 seconds.
  5. On Tech 2 select:

    6. Diagnostic Trouble Codes / Read DTC Information.

Has DTC P0742 set?

Go to Step 2

Go to Step 5

5

On Tech 2 select:

Diagnostic Trouble Codes / Read DTC Information.

Does Tech 2 display any DTCs you have not diagnosed?

Refer to Diagnostic Trouble Code (DTC) List/Type

System OK

When all diagnosis and repairs are completed, check the system for correct operation.