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.
[C-137 A/T-ECU connector (vehicle side, connected)]
Measure the voltage between the terminal No. 52 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 between the A/T-ECU connector and A/T control solenoid valve assembly connector.
Check for continuity between C-137 A/T-ECU connector and B-132 A/T control solenoid valve assembly connector.

  • Between C-137 terminal No. 52 and B-132 terminal No. 4: Continuity exists.
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 or replace the failure section.

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 between the A/T control solenoid valve assembly connector and the lock-up and low-reverse brake linear solenoid valve connector.
Check for continuity between the A/T control solenoid valve assembly connector and the lock-up and low-reverse brake linear solenoid valve connector terminals.

  • Between B-132 terminal No. 4 and the lock-up and low-reverse brake linear solenoid valve: Continuity exists.

Q. Is the check result satisfactory?
Replace the valve body assembly.
Repair or replace the failure section.

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 START.