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?
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Go to Step 2. |
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Repair or replace the failure section. |
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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?
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Go to Step 3. |
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Repair or replace the failure section. |
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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?
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Go to Step 4. |
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Repair or replace the failure section. |
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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?
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Repair or replace the failure section. |
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Go to Step 5. |
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STEP 5. Check the A/T-ECU connector pin terminal and the connection status. |
Q.
Is the check result normal?
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Replace the A/T-ECU, and then go to Step 6. |
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Repair or replace the failure section. |
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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?
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The procedure is complete. |
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Go to Step 7. |
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STEP 7. Check the installation position of the engine and A/T. |
Q.
Is the check result normal?
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Replace the transmission assembly. |
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Repair or replace the failure section. |
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