Code No. P1740: Malfunction of Lockup/Select Switching Solenoid Valve


SOLENOID VALVE SYSTEM CIRCUIT



DIAGNOSTIC FUNCTION



JUDGMENT CRITERIA



  • The status with the switching solenoid valve ON and with the monitoring value OFF is detected for 0.2 second.
  • The status with the switching solenoid valve OFF and with the monitoring value ON is detected for 0.2 seconds.

PROBABLE CAUSES



  • Malfunction of valve body assembly (Faulty lockup/select switching solenoid valve)
  • Damaged wiring harness and connectors
  • Malfunction of CVT-ECU

DIAGNOSTIC PROCEDURE

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

    Item 36: LU/SEL switching solenoid output
    Item 37: LU/SEL switching solenoid monitor
OK: Check that the output and monitor do not differ greatly.

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

STEP 2. Check the following connector:

  • B-119 CVT assembly connector
  • C-136 CVT-ECU 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. 14) and B-119 CVT assembly connector (terminal No. 4)

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

STEP 4. Lockup/select switching 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.