Code No. P0740: Malfunction of Lockup Solenoid












DIAGNOSTIC FUNCTION


CVT-ECU determines malfunction by detecting the abnormality in the lockup solenoid valve.

JUDGEMENT CRITERIA


Specified amount of current is not flown to the lockup solenoid valve because of the open or short circuit.

PROBABLE CAUSES



DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III data list

  • Item 31: Lockup solenoid output current
  • Item 30: Lockup solenoid monitoring current
OK: Check if the output current and monitoring current differ largely.

Q. Is the check result normal?
Intermittent malfunction
Go to Step 2.

STEP 2. Check the following connector:

  • C-136 CVT-ECU connector
  • B-119 CVT assembly connector
  • A-63 Intermediate connector
Check the terminals for a contact status problem and internal short circuit.

Q. Is the check result normal?
Go to Step 3.
Repair the defective connector.

STEP 3. Check for open circuit and short to earth in the wiring harness between the CVT-ECU connector and the CVT assembly connector.
Between C-136 CVT-ECU connector (terminal No. 3) and B-119 CVT assembly connector (terminal No. 3)

Q. Is the check result normal?
Go to Step 4.
Repair the wiring harness.

STEP 4. Lockup solenoid valve single unit check
Refer to .

Q. Is the check result normal?
Go to Step 5.
Replace the valve body assembly.

STEP 5. Symptom recheck after erasing diagnosis code

Q. Is the check result normal?
Intermittent malfunction
Replace CVT-ECU.