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DTC P0741: Abnormality in Lock-up Function

DIAGNOSTIC FUNCTION

Abnormality is detected by the TCM when the torque converter slip speed is high during lockup control.

DESCRIPTIONS OF MONITOR METHODS

The status with the high torque converter slip speed continues for 30 seconds during lockup control [Primary pulley speed and engine speed are normal, and lockup differential pressure is 0.2 MPa (29 psi) or more].

MONITOR EXECUTION

transmission range:D
Throttle valve opening : 1/8 or more
Engine speed : 450 r/min or more
CVT fluid temperature : from 20 to 180°C (68~356°F)

MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)

P0746: Abnormality in hydraulic control system function
P0841: Abnormality in line pressure sensor function
P0868: Secondary pressure drop

Sensor (The sensor below is determined to be normal)

Not applicable

LOGIC FLOW CHARTS (Monitor Sequence)

DTC SET CONDITIONS

Check Conditions

Transmission range switch position: D.
Throttle position sensor voltage: 1.37 volts or more.
Engine speed: 450 r/min or more.
Transmission fluid temperature: 20°C (68°F) or more.
Transmission fluid temperature: 180°C (356°F) or less.
Voltage of battery: 9 volts or more.
Voltage of battery: 16 volts or less.

Judgment Criteria

Lock-up pressure: 0.2 MPa (29 psi) or more. (30 seconds)
Torque converter slip revolution: 40+(vehicle speed/2) or more. (30 seconds)

OBD-II DRIVE CYCLE PATTERN

transmission range: D (Drive the vehicle for 30 seconds or more while the accelerator opening angle is 20% or more)

PROBABLE CAUSES

Abnormal line pressure
Malfunction of TCM

DIAGNOSTIC PROCEDURE

STEP 1. Check other diagnosis codes.

Q. Are other diagnosis codes set?

	Carry out the appropriate troubleshooting.

	Go to Step 2.

STEP 2. M.U.T.-III data list

Item 7: Primary speed
Item 9: Engine revolution

OK: No considerable difference is observed between the primary pulley speed and the engine speed.

Q. Is the check result normal?

	Intermittent malfunction

	Go to Step 3.

STEP 3. Line Pressure Check

Carry out "hydraulic test"(Refer to

).

Q. Is the check result normal?

	Go to Step 4.

	Repair according to the hydraulic pressure test diagnosis table.

STEP 4. Symptom recheck after erasing diagnosis code

Q. Is the check result normal?

	Intermittent malfunction

	Replace TCM.