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Diagnostic Item 6: Diagnose shorts in the power supply to GW-CAN-C. <Vehicles with Blind Spot Warning [BSW] (with Lane Change Assist) system>
 
 
cautionWhen servicing a CAN bus line, ground yourself by touching a metal object such as an unpainted water pipe. If you fail to do, a component connected to the CAN bus line may be broken.
 
 
TROUBLE JUDGMENT CONDITIONS
The scan tool (M.U.T.-IIISE) judges the trouble when it is impossible to receive the periodically sent data and the voltage of CAN_H or CAN_L line is more than 4.0 V.
 
 
TROUBLESHOOTING HINTS
  • Damaged harness wires and connectors
  • Malfunction of the gateway-ECU
  • Malfunction of the BSW-ECU (master)
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Check the GW-CAN-C. Voltage measurement at gateway-ECU connector.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect the gateway-ECU connector and BSW-ECU (master) connector, and measure at the wiring harness side.
(2) Connect the negative 12V starter battery terminal, and turn on the power supply mode of the electric motor switch.
(3) Voltage between the gateway-ECU connector terminal No.6 (CAN_H) and body ground.
OK: 4.0 V or less
(4) Voltage between the gateway-ECU connector terminal No.5 (CAN_L) and body ground.
OK: 4.0 V or less
(5) Disconnect the negative 12V starter battery terminal.
Is the check result normal?
<4.0 V or less> Go to Step 2.
<More than 4.0 V> Repair intermediate connectors, or the wiring harness between the gateway-ECU connector and the BSW-ECU (master) connector.
 
STEP 2. Check the GW-CAN-C. Voltage measurement at BSW-ECU (master) connector.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect the BSW-ECU (master) connector, and measure at the wiring harness side.
(2) Connect the negative 12V starter battery terminal, and turn on the power supply mode of the electric motor switch.
(3) Voltage between the BSW-ECU (master) connector terminal No.4 (CAN_H) and body ground.
OK: 4.5 V or less
(4) Voltage between the BSW-ECU (master) connector terminal No.9 (CAN_L) and body ground.
OK: 4.0 V or less
(5) Disconnect the negative 12V starter battery terminal.
Is the check result normal?
<4.5 V or less (CAN_H) and 4.0V or less (CAN_L)> Go to Step 3.
<More than 4.5 V (CAN_H) or more than 4.0 V (CAN_L)> Check the gateway-ECU connector, and repair if necessary. If the gateway-ECU connector is in good condition, replace the gateway-ECU.
 
STEP 3. Check the GW-CAN-C. Voltage measurement at gateway-ECU connector.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect the gateway-ECU connector, and measure at the wiring harness side.
(2) Connect the negative 12V starter battery terminal, and turn on the power supply mode of the electric motor switch.
(3) Voltage between the gateway-ECU connector terminal No.6 (CAN_H) and body ground.
OK: 4.5 V or less
(4) Voltage between the gateway-ECU connector terminal No.5 (CAN_L) and body ground.
OK: 4.0 V or less
(5) Disconnect the negative 12V starter battery terminal.
Is the check result normal?
<4.5 V or less (CAN_H) and 4.0V or less (CAN_L)> The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
<More than 4.5 V (CAN_H) or more than 4.0 V (CAN_L)> Check the BSW-ECU (master) connector, and repair if necessary. If the BSW-ECU (master) connector is in good condition, replace the BSW-ECU (master).