P0744

DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)

Description
This malfunction is detected when the A/T does not shift into 5th gear position or the torque converter clutch does not lock-up as instructed by the TCM. This is not only caused by electrical malfunction (circuits open or shorted) but also by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

CONSULT-III Reference Value in Data Monitor Mode:

On Board diagnosis Logic
Diagnostic trouble code "P0744 A/T TCC S/V FNCTN" with CONSULT-III or 3rd judgment flicker without CONSULT-III is detected under the following conditions.
^ When A/T cannot perform lock-up even if electrical circuit is good.
^ When TCM detects as irregular by comparing difference value with slip rotation.

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

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-III
1. Start engine.
2. Select "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III.
3. Drive vehicle and maintain the following conditions for at least 30 consecutive seconds.
ACCELE POSI: More than 1.0/8
SLCT LVR POSI: "D" position
TCC SOLENOID: 0.4 - 0.6 A
VEHICLE SPEED: 80 km/h (50 MPH) or more
Driving location: Driving the vehicle uphill (increased engine load) will help maintain the driving conditions required for this test.
4. If DTC is detected, go to "Diagnosis Procedure".

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

Diagnosis Procedure

1. CHECK INPUT SIGNAL

WITH CONSULT-III
1. Turn ignition switch ON.
2. Select "MAIN SIGNALS" in "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III.
3. Start the engine.
4. Readout 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.
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 "DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.