P0740

DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE

Description
The torque converter clutch solenoid valve is activated, with the gear in D5, M3, M4 and M5 by the TCM in response to signals sent from the vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Torque converter clutch 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 1.0/8) 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-II Reference Value:

On Board Diagnosis Logic
^ This is an OBD-II self-diagnostic item.
^ Diagnostic trouble code "P0740 TCC SOLENOID/CIRC" with CONSULT-II or 3rd judgement flicker without CONSULT-II is detected under the following conditions.
- When TCM detects an improper voltage drop when it tries to operate the solenoid valve.
- When TCM detects as irregular by comparing target value with monitor value.

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

DTC Confirmation Procedure

CAUTION: Always drive vehicle at a safe speed.

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, perform the following procedure to confirm the malfunction is eliminated.

With CONSULT-II





1. Turn ignition switch ON.
2. Select "SELECTION FROM MENU" in "DATA MONITOR" mode for "A/T" with CONSULT-II and check monitor "VHCL/S SE-A/T", "ACCELE POSI" and "SLCT LVR POSI".
3. Touch "START".
4. Start engine and maintain the following conditions for at least 5 consecutive seconds.
VHCL/S SE-A/T: 80 km/h (50 MPH) or more
ACCELE 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 DTC is detected go to AT-126, "Diagnostic Procedure".

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

Diagnostic Procedure

1. CHECK INPUT SIGNAL

With CONSULT-II








1. Turn ignition switch ON.
2. Select "MAIN SIGNALS" in "DATA MONITOR" mode for "A/T" with CONSULT-II.
3. Start engine.
4. Read out the value of "TCC SOLENOID" while driving.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.

2. CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to AT-179, "MAIN POWER SUPPLY AND GROUND CIRCUIT".
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.

3. DETECT MALFUNCTIONING ITEM
Check A/T assembly harness connector pin terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM.
NG >> Repair or replace damaged parts.

4. CHECK DTC
Perform AT-125, "DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.