DTC P0743

BHE050201026W18

DTC P0743

Torque converter clutch (TCC) solenoid valve circuit malfunction (open circuit/short to ground or power supply)

DETECTION CONDITION

• Open or short circuit in TCC solenoid signal system (when the TCM monitors solenoid output voltage, voltage that differs from the ON/OFF signal output by CPU in TCM is detected)

Diagnostic support note:

• This is continuous monitor (CCM).
• MIL illuminates if TCM detects the above malfunction condition during the first drive cycle.
• PENDING CODE is not available.
• FREEZE FRAME DATA is available.
• AT warning light illuminate.
• DTC is stored in TCM memory.

POSSIBLE CAUSE

• TCC solenoid valve malfunction
• Open circuit in wiring harness between TCC solenoid valve terminal A and TCM terminal 2W
• Short to ground in wiring harness between TCC solenoid valve terminal A and TCM terminal 2W
• Short to power supply in wiring harness between TCC solenoid valve terminal A and TCM terminal 2W
• Damaged 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 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 AT SOLENOID VALVE CONNECTOR FOR POOR CONNECTION

• Turn the ignition switch to the LOCK position.
• Disconnect the AT solenoid valve connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Are the connector and terminals normal?
Yes
Go to the next step.
No
Repair or replace the connector and/or terminal, then go to Step 13.
4

INSPECT RESISTANCE OF TCC SOLENOID VALVE

• Inspect the resistance between AT solenoid valve connector (transmission case side) terminal G and body ground.
• Is the resistance within 11.6-16.6 ohms?
Yes
Go to Step 9.
No
Go to the next step.
5

INSPECT CONTROL VALVE BODY CONNECTOR FOR POOR CONNECTION

• Disconnect the control valve body connector.
• Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
• Are the connector and terminals normal?
Yes
Go to the next step.
No
Repair or replace the connector and/or terminal, then go to Step 13.
6

INSPECT RESISTANCE OF TCC SOLENOID VALVE

• Inspect the resistance between control valve body (part-side) terminal E and body ground.
• Is the resistance within 11.6-16.6 ohms?
Yes
Repair or replace the AT solenoid valve connector harness, 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).
• Are the connector and terminals normal?
Yes
Go to the next step.
No
Repair or replace the connector and/or terminal, then go to Step 13.
8

INSPECT RESISTANCE OF TCC SOLENOID VALVE

• Inspect the resistance between TCC solenoid valve (part-side) terminal A and body ground.
• Is the resistance within 11.6-16.6 ohms?
Yes
Repair or replace the control valve body connector harness, then go to Step 13.
No
Verify the TCC solenoid valve installation.
• If the 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 connector and terminals normal?
Yes
Go to the next step.
No
Repair or replace the connector and/or terminal, then go to Step 13.
10

INSPECT AT SOLENOID VALVE CONNECTOR CIRCUIT FOR OPEN CIRCUIT

• Inspect for continuity between the TCM (wiring harness-side) terminal 2W and AT solenoid valve connector (wiring harness-side) terminal G.
• 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 AT SOLENOID VALVE CONNECTOR CIRCUIT FOR SHORT TO POWER SUPPLY

• Turn the ignition switch to the ON position (engine off).
• Inspect the voltage at AT solenoid valve connector (wiring harness-side) terminal G.
• 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 the TCM (wiring harness-side) terminal 2W 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 D range and make sure that the gears shift smoothly from 1GR to 4GR.
• 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.