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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 to 356°F)
 
 
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)
 
 
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
 
 
DIAGNOSIS
STEP 1. Check other diagnostic trouble codes.
Are other diagnostic trouble codes stored?
Carry out the appropriate troubleshooting.
Go to Step 2.
 
STEP 2. Scan tool 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.
Is the check result normal?
Intermittent malfunction
Go to Step 3.
 
STEP 3. Line Pressure Check
Carry out "hydraulic test"(Refer to ).
Is the check result normal?
Go to Step 4.
Repair according to the hydraulic pressure test diagnosis table.
 
STEP 4. Symptom recheck after erasing diagnostic trouble code
Is the check result normal?
Intermittent malfunction
Replace TCM.