P0740

DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE

Description





The torque converter clutch solenoid valve is activated, with the gear in D4, by the TCM in response to signals sent from the vehicle speed 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) in lock-up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock-up.





CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE

On Board Diagnosis Logic
Diagnostic trouble code TCC SOLENOID/CIRC with CONSULT-II or P0740 without CONSULT-II is detected when TCM detects an improper voltage drop when it tries to operate the solenoid valve.

Possible Cause
Check the following items.
- Torque converter clutch solenoid valve
- Harness or connectors (The solenoid circuit is open or shorted.)

Diagnostic Trouble Code (DTC) Confirmation Procedure

NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test. After the repair, perform the following procedure to confirm the malfunction is eliminated.

WITH CONSULT-II





1. Turn ignition switch ON.





2. Select "DATA MONITOR" mode for "ENGINE" with CONSULT-II and wait at least 1 second.

WITH GST
Follow the procedure "With CONSULT-II".

AT-TCV-01:

Wiring Diagram - AT - TCV

Diagnostic Procedure
1. CHECK VALVE RESISTANCE
1. Turn ignition switch to OFF position.
2. Disconnect terminal cord assembly connector in engine compartment.





3. Check resistance between terminal 5 and ground.
Resistance : 5 - 20 ohms
OK or NG
OK >> GO TO 3.
NG >>GO TO2.

2. CHECK VALVE OPERATION
1. Remove oil pan.





2. Check the following items:
- Torque converter clutch solenoid valve
- Check solenoid valve by listening for its operating sound while applying battery voltage to the terminal and ground.
- Harness of terminal cord assembly for short or open
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.

3. CHECK POWER SOURCE CIRCUIT
1. Turn ignition switch to OFF position.
2. Disconnect TCM harness connector.
3. Check continuity between terminal cord assembly harness connector terminal 5 and TCM harness connector terminal 3. Refer to "Wiring Diagram-AT-TCV".
Continuity should exist.
4. Reinstall any part removed.
OK or NG
OK >>GO TO4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.

4. CHECK DTC
Perform "Diagnostic Trouble Code (DTC) Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 5.

5. CHECK TCM INSPECTION
1. Perform TCM input/output signal inspection.
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.