Code No. P0743: Lock-up and Low-reverse Brake Linear Solenoid Valve System




DIAGNOSIS CODE SET CONDITIONS




PROBABLE CAUSES



  • Malfunction of the lock-up and low-reverse brake linear solenoid valve system circuit
  • Damaged harness or connector
  • Malfunction of the A/T-ECU
  • Malfunction of the lock-up and low-reverse brake linear solenoid valve (valve body assembly)

DIAGNOSIS PROCEDURE


STEP 1. Check the A/T-ECU terminal voltage.


[A/T-ECU connector (harness side, connected)]
Measure the voltage between the LULS terminal and body earth.

  • Lock-up released: 0 V
  • Lock-up engaged: 300 Hz

Q. Is the check result normal?

Go to Step 5.
Go to Step 2.

STEP 2. Check for continuity in LULS line between the A/T-ECU connector and A/T control solenoid valve assembly connector.


When the continuity check result is OK, check that the wiring harness is not shorted to the body and other wiring harness.

Q. Is the check result normal?

Go to Step 3.
Repair the connector(s) or wiring harness.

STEP 3. Check the lock-up and low-reverse brake linear solenoid.


Refer to .

Q. Is the check result normal?

Go to Step 6.
Go to Step 4.

STEP 4. Check for continuity in signal line between the A/T control solenoid valve assembly connector and the lock-up and low-reverse brake linear solenoid valve connector.


Q. Is the check result satisfactory?

Replace the valve body assembly.
Repair the connector(s) or wiring harness.

STEP 5. Check the A/T-ECU and A/T control solenoid valve assembly connector pin terminals and the connection status.


Q. Is the check result normal?

Go to Step 7.
Repair or replace the failure section.

STEP 6. Check the A/T-ECU and A/T control solenoid valve assembly connector pin terminals and the connection status.


Q. Is the check result normal?

Replace the A/T-ECU.
Repair or replace the failure section.

STEP 7. Erase the diagnosis code, and drive the vehicle for a while.


Check that the normal code is displayed.

Q. Is the check result normal?

The procedure is complete.
Return to Step 1.