P0741
DTC P0741: Torque Converter Clutch System (Stuck Off), P0742 Torque Converter Clutch System (Stuck ON)
DESCRIPTIONS OF MONITOR METHODS [P0741]
- 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)
MONITOR EXECUTION [P0741]
- Driving with the lock-up activated
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR) [P0741]
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Not applicable
LOGIC FLOW CHARTS (Monitor Sequence) [P0741]
DTC SET CONDITIONS [P0741]
Check Conditions
- Lock-up status: engaging.
- Transmission range switch: D
Judgement Criteria
- Calculated slip (engine speed - input shaft speed): (40 + 0.035 x output shaft speed])/2 or more. (30 seconds)
OBD-II DRIVE CYCLE PATTERN [P0741]
Driving at 55 km/h (34.2 mph) or more with the shift ranges of 3rd, 4th, 5th, and 6th gear. Maintain each shift range for 30 second or more.
DESCRIPTIONS OF MONITOR METHODS [P0742]
- 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)
MONITOR EXECUTION [P0742]
- Transmission range: D range driving with the lock-up activated
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR) [P0742]
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Not applicable
LOGIC FLOW CHARTS (Monitor Sequence) [P0742]
DTC SET CONDITIONS [P0742]
Check Conditions
- Output speed: more than 1,000 r/min.
- Lock-up status: disengaging.
- Transmission range switch position: D.
Judgement Criteria
- Calculated slip (engine speed - input shaft speed): 5 r/min or less. (5 seconds)
OBD-II DRIVE CYCLE PATTERN [P0742]
Driving at 55 km/h (34.2 mph) or less with the shift range of 3rd and 4th gear. Driving at 48 ± 2 km/h (29.8 ± 1.2 mph) with the 5th gear. Maintain each shift range for 1 second or more.
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)
- Malfunction of the P0743: lock-up and low-reverse brake linear solenoid valve system circuit
- Malfunction of the P0712: transmission fluid temperature sensor system (short circuit)
- Malfunction of the P0713: transmission 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
STEP 1. Hydraulic pressure test
Refer to Hydraulic Pressure Test.
Q. Is the check result normal?
YES Go to Step 2.
NO 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 P0743.
Q. Is the check result normal?
YES Go to Step 3.
NO Repair or replace the failure section.
STEP 3. Check the transmission fluid temperature sensor, input shaft speed sensor, and output shaft speed sensor.
Check the following DTCs: P0712 (transmission fluid temperature sensor (short circuit)), P0713 (transmission fluid temperature sensor (open circuit)), P0715 (input shaft speed sensor) and P0720 (output shaft speed sensor).
Refer to P0712 [P0712], P0713 [P0713], P0715 [P0715], P0720 [P0720].
Q. Is the check result normal?
YES Go to Step 4.
NO Repair or replace the failure section.
STEP 4. Check the malfunction of CAN communication system.
Q. Are the DTC for CAN communication system malfunction (U0001, U0100, U0141, P1705, P1706) set?
YES Repair or replace the failure section.
NO Go to Step 5.
STEP 5. Check the TCM connector pin terminal and the connection status.
Q. Is the check result normal?
YES Replace the TCM, and then go to Step 6.
NO Repair or replace the failure section.
STEP 6. Erase the DTC code, and drive the vehicle for a while.
Check that the normal code is displayed.
Q. Is the check result normal?
YES The procedure is complete.
NO Go to Step 7.
STEP 7. Check the installation position of the engine and A/T.
Q. Is the check result normal?
YES Replace the transaxle assembly.
NO Repair or replace the failure section.