P0740

DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE

Description
- The torque converter clutch solenoid valve is activated by the TCM in response to signals sent from the vehicle speed and accelerator pedal position sensors. Lock-up piston operation will then be controlled.
- Lock-up operation, however, is prohibited when CVT fluid temperature is too low.
- When the accelerator pedal is depressed (less than 2.0/8) 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-III Reference Value:

On Board Diagnosis Logic
- This is an OBD-II self-diagnostic item.
- Diagnostic trouble code "P0740 TCC SOLENOID/CIRC" with CONSULT-III is detected under the following conditions.
- TCM detects an improper voltage drop when it tries to operate the solenoid valve.

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

DTC Confirmation Procedure

NOTE:
If "DTC Confirmation Procedure" has been previously performed, always turn ignition switch OFF and wait at least 10 seconds before performing the next test.

After the repair, touch "ERASE" on "SELF-DIAG RESULTS" and then perform the following procedure to confirm the malfunction is eliminated.

WITH CONSULT-III
1. Turn ignition switch ON.
2. Select "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III and wait at least 10 consecutive seconds.
3. If DTC is detected, go to CVT-85, Diagnostic Procedure".

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

Wiring Diagram - CVT - TCV

CVT-TCV-01:

TCM TERMINALS AND REFERENCE VALUES
Refer to CVT-44, "TCM Input/Output Signal Reference Value". Pinout Values and Diagnostic Parameters

Diagnostic 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. Start vehicle and read out the value of "ISOLT1".





Without CONSULT-III
1. Start engine.
2. Check voltage between TCM connector terminal and ground.





3. Turn ignition switch OFF.
4. Disconnect TCM connector.
5. Check if there is continuity between the 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 TORQUE CONVERTER CLUTCH SOLENOID VALVE
1. Turn ignition switch OFF.
2. Disconnect TCM connector (A) and CVT unit harness connector (B).








3. Check continuity between TCM connector terminal (A) and CVT unit harness connector terminal (B).
4. If OK, check harness for short to ground and short to power.
5. If OK, check continuity between ground and CVT assembly.
6. Reinstall any part removed.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.

4.CHECK VALVE RESISTANCE
1. Turn ignition switch OFF.
2. Disconnect CVT unit harness connector.








3. Check resistance between CVT unit harness connector terminal and ground.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.

5.CHECK DTC
Perform CVT-83, "DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 6.

6.CHECK TCM
1. Check TCM input/output signals. Refer to CVT-44, "TCM Input/Output Signal Reference Value". Pinout Values and Diagnostic Parameters
2. If NG, re-check 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
1. Turn ignition switch OFF.
2. Disconnect CVT unit harness connector.








3. Check resistance between CVT unit harness connector terminal and ground.
4. If NG, replace the transaxle assembly.