Inspection Procedure
1: Power supply to the BSW-ECU (master) fails (Cannot communicate with BSW-ECU (master) using
the M.U.T.-III.)
caution |
When replacing the ECU, always
check that the communication circuit is normal.
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COMMENTS ON TROUBLE SYMPTOM
BSW-ECU (master) is communicating with M.U.T.-III via CAN. Therefore, communication error of
BSW-ECU (master) is suspected.
PROBABLE CAUSES
- Malfunction of the power supply and the earth of BSW-ECU (master)
- Malfunction of BSW-ECU (master)
DIAGNOSIS PROCEDURE
STEP 1. Resistance measurement at BSW-ECU (master) connector
terminal GND.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the resistance between the BSW-ECU (master) connector terminal GND and
body earth. OK: Continuity exists (2 Ω or less)
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Q.
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.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the ignition switch from the LOCK (OFF) position to the ON position.
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(3)Check the voltage between the BSW-ECU (master) connector terminal IG and body earth. OK: System voltage
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Q.
Is the check result normal?
Go to Step 3
Repair the connector(s) or wiring harness.
STEP 3. Retest the system
Check if M.U.T.-III can communicate with the BSW-ECU (master).
Q.
Is the check result normal?
Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use
Troubleshooting/Inspection Service Points - How to cope with Intermittent Malfunction).
Replace the BSW-ECU (master).