Inspection Procedure 9: Malfunction of the CAN Converter-ECU power supply circuit.

caution

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

PROBABLE CAUSES

Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Connector check: D-252 CAN converter-ECU connector

Q. Is the check result normal?

STEP 2. Voltage measurement at the D-252 CAN converter-ECU connector.

(1)Disconnect the CAN converter-ECU connector, and measure at the wiring harness side.

(2)Measure the voltage between D-252 CAN converter-ECU connector terminal No. 1 and body earth.
OK: System voltage

(3)With the ignition switch turned to the "ON" position, measure the voltage between D-252 CAN converter-ECU connector terminal No. 2 and body earth.
OK: System voltage

Q. Is the check result normal?

STEP 3. Check the wiring harness between D-252 CAN converter-ECU connector terminal No. 1 and fusible link (1), or between D-252 CAN converter-ECU connector terminal No. 2 and ignition switch (IG1).

note

Prior to the wiring harness inspection, check intermediate connector D-241 and junction block connector D-403 and D-405, and repair if necessary.

Check the power supply line for open circuit and short circuit.

Q. Is the check result normal?

STEP 4. Resistance measurement at the D-252 CAN converter-ECU connector.

(1)Disconnect the CAN converter-ECU connector, and measure at the wiring harness side.

(2)Continuity between D-252 CAN converter-ECU connector terminal No.16 and body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?

STEP 5. Check the wiring harness between D-252 CAN converter-ECU connector terminal No.16 and body earth.

Check the earth wires for open circuit.