Code No. P0741: Torque Converter Clutch System (Stuck Off), P0742 Torque Converter Clutch System (Stuck ON)




DIAGNOSIS CODE SET CONDITIONS
  • When the input shaft speed sensor is normal, the engine speed signal is normal, and within the lock-up operation range, the slip speed of the torque converter exceeds the specified value. <P0741>
  • When the input shaft speed sensor and the output shaft speed sensor are normal at the "D" range, the engine speed signal is normal, and within the non-lock-up operation range, the extremely low slip speed of the torque converter is detected continuously for a specified time. <P0742>

PROBABLE CAUSES



  • Malfunction of the P0743: lock-up and low-reverse brake linear solenoid valve system circuit
  • Malfunction of the P0712: A/T fluid temperature sensor system (short circuit)
  • Malfunction of the P0713: A/T fluid temperature sensor system (open circuit)
  • Poor installation of the engine and A/T (deviation to the axial direction)
  • Malfunction of the torque converter
  • Malfunction of the valve body assembly

DIAGNOSIS PROCEDURE


STEP 1. Hydraulic pressure test


Refer to .

Q. Is the check result normal?

Go to Step 2.
Repair or replace the failure section.

STEP 2. Check the lock-up and low-reverse brake linear solenoid.


Check for P0743 (lock-up and low-reverse brake linear solenoid). Refer to .

Q. Is the check result normal?

Go to Step 3.
Repair or replace the failure section.

STEP 3. Check the A/T fluid temperature sensor, input shaft speed sensor, and output shaft speed sensor.


Check the following diagnosis codes: P0712 (A/T fluid temperature sensor (short circuit)), P0713 (A/T fluid temperature sensor (open circuit)), P0715 (input shaft speed sensor) and P0720 (output shaft speed sensor).
Refer to <P0712>, <P0713>, <P0715>, <P0720>.

Q. Is the check result normal?

Go to Step 4.
Repair or replace the failure section.

STEP 4. Check the malfunction of CAN communication system.


Q. Are the diagnosis code for CAN communication system malfunction (U0001, U0100, U0141, P1705, P1706) set?

Repair or replace the failure section.
Go to Step 5.

STEP 5. Check the A/T-ECU connector pin terminal and the connection status.


Q. Is the check result normal?

Replace the A/T-ECU, and then go to Step 6.
Repair or replace the failure section.

STEP 6. Erase the diagnosis code, and drive the vehicle for a while.


Check that the normal code is displayed.

Q. Is the check result normal?

The procedure is complete.
Go to Step 7.

STEP 7. Check the installation position of the engine and A/T.


Q. Is the check result normal?

Replace the transmission assembly.
Repair or replace the failure section.