P0744

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





Description
- This malfunction will not be detected while the O/D OFF indicator lamp is indicating another self-diagnosis malfunction.
- This malfunction is detected when the torque converter clutch does not lock up as instructed by the TCM.
This is not caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, malfunctioning oil pump or torque converter clutch, etc.




On Board Diagnosis Logic
- This is an OBD-II self-diagnostic item.
- Diagnostic trouble code "A/T TCC S/V FNCTN" with CONSULT-III or P0744 without CONSULT-III is detected when A/T cannot perform lock-up even if electrical circuit is good.




Possible Cause
- Shift solenoid valve D
(Off stick.)
- Pressure control solenoid valve C
(Off stick.)
- Torque converter clutch
- Hydraulic control circuit




DTC Confirmation Procedure

CAUTION:
- Always drive vehicle at a safe speed.
- Be careful not to rev engine into the red zone on the tachometer.

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 and select "DATA MONITOR" mode for "TRANSMISSION" with CONSULT-III.
2. Make sure that ATF temperature is within the range below.
FLUID TEMP: More than 20�C (68�F)
If out of range, drive the vehicle to warm up the fluid.
3. Accelerate vehicle to more than 100 km/h (62 MPH) and maintain the following conditions for at least 12 consecutive seconds.
SLCT LVR POSI: "D" position
GEAR: 5th position
SLIP REV: Less than 100 rpm
ACCELE ANGLE: More than 5 %
LOCK-UP: ON (Refer to Shift Schedule.)
[Vehicle speed: Constant speed of more than 100 km/h (62 MPH).]
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".




Wiring Diagram - AT - TCCSIG

AT-TCCSIG-01:

TCM Input/Output Signal Reference Values. Refer to Pinout Values and Diagnostic Parameters.




Diagnosis Procedure
1.CHECK SHIFT SOLENOID VALVE D CIRCUIT
Perform "Diagnostic Procedure" for DTC P0765. Refer to P0765.
OK or NG
OK - GO TO 2.
NG - Repair or replace damaged parts.
2.CHECK PRESSURE CONTROL SOLENOID VALVE C CIRCUIT
Perform "Diagnostic Procedure" for DTC P0795. Refer to P0795.
OK or NG
OK - GO TO 3.
NG - Repair or replace damaged parts.
3.CHECK MALFUNCTIONING ITEM
1. Control valve assembly. Refer to Service and Repair.
2. Disassemble A/T. Refer to Disassembly.
3. Check the following item:
- Torque converter clutch. Refer to Disassembly.
OK or NG
OK - GO TO 4.
NG - Repair or replace damaged parts.
4.CHECK DTC
Perform "DTC Confirmation Procedure". Refer to "DTC Confirmation Procedure".
OK or NG
OK - INSPECTION END
NG - Replace the control valve assembly. Refer to Service and Repair.