Inspection Procedure 8: Power supply or communication circuit to the CAN box unit is defective.


caution Before replacing the CAN box unit, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

PROBABLE CAUSES

  • Malfunction of CAN box unit
  • Malfunction of multivision display
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check the multivision display
Check if the multivision display power is turned ON.

Q. Is the check result normal?
Go to Step 2
Perform Inspection Procedure 1 "No navigation screen is displayed."(Refer to .)

STEP 2. Voltage measurement at CAN box unit connector (+B, ACC terminal).
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Check the voltage between the DAB tuner connector (+B, ACC 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 +B, ACC line between CAN box unit connector and joint connector

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 ).
Repair the connector(s) or wiring harness.

STEP 4. Resistance measurement at CAN box unit connector (GND terminal).
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Check the continuity between the CAN box unit 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 CAN box unit connector and body earth

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 ).
Repair the connector(s) or wiring harness.

STEP 6. Check of short or open circuit in TX-C, RX-C, CK-C, SH-C line between CAN box unit connector and multivision display connector

Q. Is the check result normal?
Replace the CAN box unit.
Repair the connector(s) or wiring harness.