Torque Converter

P0740 TORQUE CONVERTER





Description
- The torque converter clutch solenoid valve is activated, with the gear in D4 and D3, by the TCM in response to signals sent from the output speed sensor and the ECM (throttle opening). Lock-up piston operation will then be controlled.
- Lock-up operation, however, is prohibited when A/T fluid temperature is too low.
- When the accelerator pedal is depressed (less than 2/8) on lock-up condition, the engine speed should not change abruptly. If there is an abrupt change in engine speed, there is no lock-up.




CONSULT-III Reference Value in Data Monitor Mode









On Board Diagnosis Logic
- This is an OBD-II self-diagnostic item.
- Diagnostic trouble code "P0740 T/C CLUTCH SOL" with CONSULT-III or 7th judgement flicker without CONSULT-III is detected when TCM detects an improper voltage drop while it tries to operate solenoid valve.




Possible Cause
- Torque converter clutch solenoid valve
- Harness or connector
(The solenoid circuit is open or shorted.)




DTC Confirmation Procedure

CAUTION:
- Always drive vehicle at a safe speed.
- If performing this "DTC Confirmation Procedure" again, always turn ignition switch OFF and wait at least 10 seconds before continuing.
After the repair, perform the following procedure to confirm the malfunction is eliminated.

WITH CONSULT-III
1. Turn ignition switch ON. (Do not start engine.)
2. Select "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III and wait at least 1 second.
3. Touch "START".
4. Start engine and maintain the following conditions for at least 5 consecutive seconds.
VEHICLE SPEED: 80 km/h (50 MPH) or more
THROTTLE POSI: 0.5/8 - 1.0/8
SLCT LVR POSI: "D" position
Driving location: Driving the vehicle uphill (increased engine load) will help maintain the driving conditions required for this test.
5. If the check result is NG, go to SEE Diagnosis Procedure.

WITH GST
Follow the procedure "WITH CONSULT-III".

WITHOUT CONSULT-III
1. Start engine.
2. Drive vehicle in D1 to D2 to D3 to D4 to D4 lock-up position.
3. Perform self-diagnosis. Automatic Transmission .
4. If the check result is NG, go to SEE Diagnosis Procedure .




Wiring Diagram - AT - TCV






TCM TERMINALS AND REFERENCE VALUES
Automatic Transmission.




Diagnosis Procedure
1.CHECK INPUT SIGNAL
With CONSULT-III
1. Start engine.
2. Select "MAIN SIGNALS" in "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III.
3. Read out the value of "TCC S/V DUTY" while driving. Check the value changes according to driving speed.





Without CONSULT-III
1. Start engine.





2. Check voltage between TCM connector terminal and ground.





OK or NG
OK - GO TO 5.
NG - GO TO 2.
2.CHECK TORQUE CONVERTER CLUTCH SOLENOID VALVE CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect TCM connector.





3. Check resistance between TCM connector terminal and ground.





OK or NG
OK - GO TO 5.
NG - GO TO 3.
3. CHECK HARNESS BETWEEN TCM AND TERMINAL CORD ASSEMBLY HARNESS CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect terminal cord assembly harness connector and TCM connector.





3. Check continuity between terminal cord assembly harness connector terminal and TCM connector terminal.





4. If OK, check harness for short to ground and short to power.
5. If OK, check continuity between ground and transaxle assembly.
6. Reinstall any part removed.
OK or NG
OK - GO TO 4.
NG - Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK VALVE RESISTANCE
1. Turn ignition switch OFF.
2. Disconnect terminal cord assembly connector in engine room.





3. Check resistance between terminal cord assembly harness connector terminal and ground.





OK or NG
OK - GO TO 5.
NG - Repair or replace damaged parts.
5.CHECK DTC
Perform SEE DTC Confirmation Procedure .
OK or NG
OK - INSPECTION END
NG - GO TO 6.
6.CHECK TCM
1. Check TCM input/output signal. Automatic Transmission .
2. If NG, recheck TCM pin terminals for damage or loose connection with harness connector.
OK or NG
OK - INSPECTION END
NG - Repair or replace damaged parts.




Component Inspection

TORQUE CONVERTER CLUTCH SOLENOID VALVE
- For removal, Service and Repair .

Resistance Check





- Check resistance between terminal and ground.






Operation Check





- Check solenoid valve by listening for its operating sound while applying battery voltage to the terminal and ground.