[Previous][Next]
Inspection Procedure 1: Power supply to the BSW-ECU (master) fails [Cannot communicate with BSW-ECU (master) using the scan tool (M.U.T.-III)]
 
 
cautionWhen replacing the ECU, always check that the communication circuit is normal.
 
 
COMMENTS ON TROUBLE SYMPTOM
BSW-ECU (master) is communicating with scan tool (M.U.T.-III) via CAN. Therefore, communication error of BSW-ECU (master) is suspected.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the power supply and the ground of BSW-ECU (master)
  • Malfunction of BSW-ECU (master)
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Resistance measurement at BSW-ECU (master) connector terminal GND.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Measure the resistance between the BSW-ECU (master) connector terminal GND and ground.
OK: Continuity exists (2 ohms or less)
Is the check result normal?
Go to Step 2.
Repair the connector(s) or wiring harness.
 
STEP 2. Voltage measurement at BSW-ECU (master) 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 (master) connector terminal IG and ground.
OK: Battery positive voltage
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
 
STEP 3. Retest the system
Check if scan tool (M.U.T.-III) can communicate with the BSW-ECU (master).
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 ).
Replace the BSW-ECU (master).