STEP 1. Using scan tool (M.U.T.-III), diagnose the CAN bus line.
(1) caution | To prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III). |
Connect scan tool (M.U.T.-III). Refer to "How to connect the Scan Tool (M.U.T.-III)
."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the CAN bus line found to be normal?
Go to Step 2. Repair the CAN bus line (Refer to GROUP 54C - Diagnosis <CAN>, CAN Bus Diagnostic Table ).
STEP 2. Resistance measurement at BSW-ECU (slave) connector terminal GND.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the BSW-ECU (slave) connector terminal GND and ground.OK: Continuity exists (2 ohms or less)
Is the check result normal?
Go to Step 3. Repair the connector(s) or wiring harness.
STEP 3. Voltage measurement at BSW-ECU (slave) connector terminal IG.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Turn the ignition switch from the LOCK (OFF) position to the ON position.
(3) Check the voltage between the BSW-ECU (slave) connector terminal IG and ground.OK: Battery positive voltage
Is the check result normal?
Go to Step 4. Repair the connector(s) or wiring harness.
STEP 4. Check of short and open circuit in CNH2 and CNL2 line between BSW-ECU (master) connector and BSW-ECU (slave) connector
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the BSW-ECU (master) connector terminal CNH2 and the BSW-ECU (slave) connector terminal CNH2, and between the BSW-ECU (master) connector terminal CNL2 and the BSW-ECU (slave) connector terminal CNL2.OK: Continuity exists (2 ohms or less)
(3) Measure the resistance between the BSW-ECU (master) connector terminal CNH2 and ground, and between the BSW-ECU (master) connector terminal CNL2 and ground.OK: No continuity
(4) Measure the resistance between the BSW-ECU (master) connector terminal CNH2 and any of the other terminals, and between the BSW-ECU (master) connector terminal CNL2 and any of the other terminals.OK: No continuity
Is the check result normal?
Go to Step 5. Repair the connector(s) or wiring harness.
STEP 5. Measure the terminal resistance at the BSW-ECU.
caution | A digital multimeter should be used. For details refer to . |
(1) Remove the BSW-ECU (master/slave), and measure at the equipment side.
(2) Resistance between the BSW-ECU (master) connector terminal CNH2 and CNL2.OK: 120 ± 20 Ω
(3) Resistance between the BSW-ECU (slave) connector terminal CNH2 and CNL2.OK: 120 ± 20 Ω
Is the check result normal?
Go to Step 6. Replace a defective ECU.
STEP 6. Using scan tool (M.U.T.-III), read the BSW-ECU (master) DTC again.
Check again if the DTC is set in the BSW-ECU (master).(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is set.
Is the DTC set?
Replace the BSW-ECU (slave). Then go to Step 7. The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
STEP 7. Using scan tool (M.U.T.-III), read the BSW-ECU (master) DTC again.
Check again if the DTC is set in the BSW-ECU (master).(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is set.
Is the DTC set?
Use the BSW-ECU (slave), which has been removed at step 6, as the BSW-ECU (master). This diagnosis is complete.