DTC P0743 [JA5A-EL]

BME050218901213

DTC P0743

Torque converter clutch (TCC) solenoid valve circuit malfunction (open/short)

DETECTION CONDITION

• If there is open or short circuit in the TCC solenoid signal system (while the TCM monitors the solenoid output voltage, the voltage that differs from the ON/OFF signal output by the CPU in TCM is detected), the TCM determines that there is a malfunction.
Diagnostic support note:
• This is continuous monitor (CCM).
• The MIL illuminates if the TCM detects the above malfunction condition during the first drive cycle.
• PENDING CODE is not available.
• FREEZE FRAME DATA is available.
• The HOLD indicator light flashes.
• The DTC is stored in the TCM memory.

POSSIBLE CAUSE

• Open circuit in wiring harness between TCC solenoid valve terminal A and TCM terminal 2S
• Short to ground in wiring harness between TCC solenoid valve terminal A and TCM terminal 2S
• Short to power supply in wiring harness between TCC solenoid valve terminal A and TCM terminal 2S
• TCC solenoid valve malfunction
• Damage connector between TCC solenoid valve and TCM
• TCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
• Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME PID DATA on the repair order, then go to the next step.
2
VERIFY RELATED REPAIR INFORMATION AVAILABILITY
• Verify related Service Bulletins and/or on-line repair information availability.
• Is any related repair information available?
Yes
Perform repair or diagnosis according to the available repair information.
• If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
INSPECT TERMINAL COMPONENT NO.1 (12-PIN) FOR POOR CONNECTION
• Turn the ignition switch to the LOCK position.
• Disconnect the terminal component No.1 (12-pin).
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Are the terminals normal?
Yes
Go to the next step.
No
Repair or replace the terminals, then go to Step 13.
4
INSPECT RESISTANCE
• Inspect the resistance between terminal component No.1 (12-pin) terminal H (transaxle case side) and body ground.
• Is the resistance within 12-13.2 ohms?
Yes
Go to Step 9.
No
Go to the next step.
5
INSPECT COUPLER COMPONENT (10-PIN) FOR POOR CONNECTION
• Disconnect the coupler component (10-pin) connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Is the terminal normal?
Yes
Go to the next step.
No
Repair or replace the terminal, then go to Step 13.
6
INSPECT RESISTANCE
• Inspect the resistance between coupler component (10-pin) terminal C (part side) and body ground.
• Is the resistance within 12-13.2 ohms?
Yes
Repair or replace terminal component No.1 (12-pin), then go to Step 13.
No
Go to the next step.
7
INSPECT TCC SOLENOID VALVE CONNECTOR FOR POOR CONNECTION
• Disconnect the TCC solenoid valve connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Is the terminal normal?
Yes
Go to the next step.
No
Repair or replace the terminal, then go to Step 13.
8
INSPECT RESISTANCE
• Inspect the resistance between TCC solenoid valve connector (part side) terminal A and body ground.
• Is the resistance within 12-13.2 ohms?
Yes
Repair or replace the coupler component (10-pin), then go to Step 13.
No
Verify the TCC solenoid valve installation.
• If TCC solenoid valve is installed correctly, replace the TCC solenoid valve, then go to Step 13.
9
INSPECT TCM CONNECTOR FOR POOR CONNECTION
• Disconnect the TCM connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Are the terminals normal?
Yes
Go to the next step.
No
Repair the terminals, then go to Step 13.
10
INSPECT TERMINAL COMPONENT NO.1 (12-PIN) CIRCUIT FOR OPEN CIRCUIT
• Inspect for continuity between TCM terminal 2S (wiring harness-side) and terminal component No.1 (12-pin) terminal H (wiring harness-side).
• Is there continuity between the terminals?
Yes
Go to the next step.
No
Repair or replace the wiring harness, then go to Step 13.
11
INSPECT TERMINAL COMPONENT NO.1 (12-PIN) CIRCUIT FOR SHORT TO POWER SUPPLY
• Turn the ignition switch to the ON position (engine off).
• Inspect the voltage at terminal component No.1 (12-pin) terminal H (wiring harness-side).
• Is the voltage 0 V?
Yes
Go to the next step.
No
Repair or replace the wiring harness, then go to Step 13.
12
INSPECT TCM CIRCUIT FOR SHORT TO GROUND
• Turn the ignition switch to the LOCK position.
• Inspect for continuity between TCM terminal 2S (wiring harness-side) and body ground.
• Is there continuity?
Yes
Repair or replace the wiring harness, then go to the next step.
No
Go to the next step.
13
VERIFY TROUBLESHOOTING OF DTC P0743 COMPLETED
• Make sure to reconnect all disconnected connectors.
• Clear the DTC from the TCM memory using the WDS or equivalent.
• Drive the vehicle in the D range and make sure that gears shift smoothly from 1GR to 5GR.
• Is the same DTC present?
Yes
Replace the TCM, then go to the next step.
No
Go to the next step.
14
VERIFY AFTER REPAIR PROCEDURE
• Perform the "After Repair Procedure".
• Are any DTCs present?
Yes
Go to the applicable DTC inspection.
No
DTC troubleshooting completed.