Inspection Procedure 1: CVT-ECU cannot communicate with M.U.T.-III <Vehicles with AS&G system>


SYMPTOMS


CVT-ECU cannot be turned ON.

PROBABLE CAUSES



DIAGNOSTIC PROCEDURE

STEP 1. Perform voltage measurement at CVT-ECU connector (VIG1, VIG2 terminal).
(1)Disconnect the CVT-ECU connector and measure the voltage between VIG1, VIG2 terminals and earth at wiring harness side.
(2)Turn the ignition switch to the "ON" position.
OK: System voltage

Q. Is the check result normal?
Go to Step 3.
Go to Step 2.

STEP 2. Check for open circuit or short to earth in VIG1, VIG2 line between the DC/DC converter connector and the CVT-ECU connector.

Q. Is the check result normal?
Carry out SYMPTOM PROCEDURES Inspection procedure 7: Checking the DC/DC Converter Power Supply System. (Refer to ).
Repair the connector(s) or wiring harness.

STEP 3. Perform resistance measurement at CVT-ECU connector (GND1, GND2 terminal).
Disconnect the CVT-ECU connector and measure the resistance between GND1, GND2 terminals and earth at wiring harness side.
OK: Continuity exist (2 Ω or less).

Q. Is the check result normal?
Go to Step 5.
Go to Step 4.

STEP 4. Check for open circuit in GND1, GND2 line between the CVT-ECU connector and earth.

Q. Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.

STEP 5. Recheck the trouble symptom.

Q. Does the malfunction take place again?
Replace the CVT-ECU.
Intermittent malfunction