Inspection Procedure 11: Cannot communicate with EV remote-ECU using the M.U.T.-III.



caution
  • Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

COMMENTS ON TROUBLE SYMPTOM


If M.U.T.-III cannot communicate with the EV remote-ECU, the CAN bus lines may be faulty. If the EV remote-ECU does not work, the EV remote-ECU or its power supply circuit may be faulty.

PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III CAN bus diagnostics


Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?

Go to Step 2

Repair the CAN bus lines. (Refer to GROUP 54C - Troubleshooting .)

STEP 2. Voltage measurement at EV remote-ECU connector (IG2, +B) terminal.


(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the power supply mode of the electric motor switch from LOCK to ON.
(3)Check the voltage between the EV remote-ECU connector IG2 terminal and body earth.
OK: System voltage
Check the voltage between the EV remote-ECU connector +B terminal and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 4

Go to Step 3

STEP 3. Check of short to power supply, short to earth, and open circuit in (IG2, +B) line between fusible link and EV remote-ECU connector.


Q. Is the check result normal?

Go to Step 4

Repair the power supply circuit to EV remote-ECU.

STEP 4. Resistance measurement at EV remote-ECU connector (GND terminal)


(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the EV remote-ECU connector (GND terminal) and body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

Go to Step 6

Go to Step 5

STEP 5. Check of open circuit in GND line between EV remote-ECU connector and body earth.


Q. Is the check result normal?

Go to Step 6

Repair the earth circuit to EV remote-ECU.

STEP 6. Retest the system.


Check if M.U.T.-III can communicate with EV remote-ECU.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).

NO : Replace the EV remote-ECU.