P0740

P0740 TORQUE CONVERTER

Description

- The torque converter clutch solenoid valve is activated, with the gear in D4, D5 by the TCM in response to signals sent from the output 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 1/8) 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 Reference Value in Data Monitor Mode








On Board Diagnosis Logic

- This is an OBD-II self-diagnostic item.
- Diagnostic trouble code "P0740" with CONSULT or 3rd judgment flicker without CONSULT 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 (The 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

1.Turn ignition switch "ON". (Do not start engine.)
2.Select "DATA MONITOR" mode for "TRANSMISSION" with CONSULT.
3.Start engine and maintain the following conditions for at least 5 consecutive seconds.
VHCL/S SE-AT: 80 km/h (50 MPH) or more
ACCEL 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.
4.If DTC is detected go to Diagnosis Procedure (see below).

WITH GST

Follow the procedure "WITH CONSULT".


Diagnosis Procedure


1. CHECK INPUT SIGNAL

With CONSULT
1.Turn ignition switch ON.
2.Select "MAIN SIGNALS" in "DATA MONITOR" mode for "TRANSMISSION" with CONSULT.
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. Main Power Supply And Ground Circuit.
OK or NG
OK- GO TO 3.
NG- Repair or replace damaged parts.

3. DETECT MALFUNCTIONING ITEM

Check the following.
- The 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. Service and Repair.
NG- Repair or replace damaged parts.

4. CHECK DTC

Perform "DTC Confirmation Procedure".
- .
OK or NG
OK-INSPECTION END
NG- GO TO 2.