P0742

DTC P0741: Torque Converter Clutch System (Stuck Off), P0742 Torque Converter Clutch System (Stuck ON)

DESCRIPTIONS OF MONITOR METHODS
^ 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
^ Continuous

MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)

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)

Logic Flow Charts (Monitor Sequence):

DTC SET CONDITIONS

Check Conditions
^ Solenoid status: plunging into connecting condition.
^ Crankshaft position sensor: normality.
^ Input shaft speed sensor: normality.

Judgement Criteria
^ Calculated slip (engine speed - input shaft speed): (40 + [vehicle speed/2>). (30 seconds)

DESCRIPTIONS OF MONITOR METHODS
^ 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
^ Continuous

OBD-II DRIVE CYCLE PATTERN
Start the engine, and drive at 100 km/h (62 mph) for 10 seconds. Then stop the vehicle, and turn OFF the ignition switch. After that, restart the engine, and drive again at 100 km/h (62 mph) for 10 seconds.

MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)

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)

Logic Flow Charts (Monitor Sequence):

DTC SET CONDITIONS

Check Conditions
^ Output speed: more than 1,000 r/min.
^ Solenoid status: 5 seconds after not plunging into connecting condition.
^ Transmission range switch position: D.
^ Input shaft speed sensor: normality.
^ Output shaft speed sensor: normality.

Judgement Criteria
^ Calculated slip (engine speed - input shaft speed): 5 r/min or less. (5 seconds)

OBD-II DRIVE CYCLE PATTERN
Start the engine, and drive at 30 km/h (19 mph) for 30 seconds. Then stop the vehicle, and turn "LOCK" (OFF) the ignition switch. After that, restart the engine, and drive again at 30 km/h (19 mph) for 30 seconds.

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

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).

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>, [P0713>, [P0715>, [P0720>. P0712 P0713 P0715 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.