DTC P0743[LA4AX-EL (CD4E)]


id050207806500

DTC P0743

Torque converter clutch (TCC) control solenoid valve circuit malfunction

DETECTION CONDITION
•  Open or short circuit in circuit between torque converter clutch control solenoid valve and PCM, or in torque converter clutch control solenoid valve internal circuit.
POSSIBLE CAUSE
•  TCC control solenoid valve malfunction.
•  Main relay and fuse malfunction.
•  Short to ground in wiring harness between main relay and ATX connector terminal B (transaxle case side).
•  Open circuit in wiring harness between main relay and ATX connector terminal B (transaxle case side).
•  Short to ground in wiring harness between ATX connector terminal J (wiring harness-side) and PCM terminal 54 (wiring harness-side).
•  Short to power supply in wiring harness between ATX connector terminal J (wiring harness-side) and PCM terminal 54 (wiring harness-side).
•  Open circuit in wiring harness between ATX connector terminal J (wiring harness-side) and PCM terminal 54 (wiring harness-side).
•  Damaged connector between TCC control solenoid valve and PCM.
•  PCM malfunction.

Diagnostic procedure

STEP

INSPECTION

ACTION

1
VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
•  Has the 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 SERVICE INFORMATION AVAILABILITY
•  Verify related Service Information availability.
•  Is any related Service Information available?
Yes
Perform repair or diagnosis according to the available Service Information.
•  If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
INSPECT ATX CONNECTOR FOR POOR CONNECTION
•  Turn the ignition switch to the LOCK position.
•  Inspect ATX connector connection.
•  Disconnect the ATX connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is the connection normal?
Yes
Go to the next step.
No
Repair or replace the connector and/or terminals, then go to Step 10.
4
INSPECT POWER SUPPLY CIRCUIT
•  Turn the ignition switch to the ON position (engine off).
•  Inspect voltage at ATX connector terminal B (wiring harness-side).
•  Is the voltage approx. 12 V?
Yes
Go to the next step.
No
Inspect the fuse, main relay and wiring harness, then go to Step 10.
5
INSPECT RESISTANCE
•  Turn the ignition switch to the LOCK position.
•  Inspect resistance between ATX terminal B and J (transaxle case side).
•  Is resistance within 12.5—19.0 ohms?
Yes
Go to the next step.
No
Replace the TCC control solenoid valve, then go to Step 10.
6
INSPECT PCM CONNECTOR FOR POOR CONNECTION
•  Disconnect the PCM connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is the connection normal?
Yes
Go to the next step.
No
Repair or replace connector and/or terminals, then go to Step 10.
7
INSPECT TCC CONTROL SOLENOID VALVE CIRCUIT FOR OPEN CIRCUIT
•  Inspect for continuity between PCM terminal 54 (wiring harness-side) and ATX connector terminal J (wiring harness-side).
•  Is there continuity between terminals?
Yes
Go to the next step.
No
Repair or replace the wiring harness, then go to Step 10.
8
INSPECT TCC CONTROL SOLENOID VALVE CIRCUIT FOR SHORT TO GROUND
•  Turn the ignition switch to the LOCK position.
•  Inspect continuity between ATX connector terminal J (wiring harness-side) and body ground.
•  Is there continuity?
Yes
Repair or replace the wiring harness, then go to the Step 10.
No
Go to the next step.
9
INSPECT TCC CONTROL SOLENOID VALVE CIRCUIT FOR SHORT TO POWER SUPPLY
•  Turn the ignition switch to the ON position (engine off).
•  Inspect voltage at ATX connector terminal J (wiring harness-side).
•  Is the voltage 0 V?
Yes
Go to the next step.
No
Repair or replace the wiring harness, then go to the next step.
10
VERIFY TROUBLESHOOTING OF DTC P0743 COMPLETED
•  Make sure to reconnect all the disconnected connectors.
•  Clear the DTC from memory using the M-MDS.
•  Perform the “After Repair Procedure”.
•  Are any DTCs present?
Yes
Replace the PCM, then go to the next step.
No
Go to the next step.
11
VERIFY DTCS
•  Are except DTC P0743 output?
Yes
Go to the applicable DTC inspection.
No
DTC troubleshooting completed.