[Previous][Next]
Diagnostic Item 31: Diagnose when the scan tool (M.U.T.-IIISE) cannot receive the data sent by BSW-ECU (master). <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.
 
 
FUNCTION
The diagnostic result demonstrates that "the scan tool (M.U.T.-IIISE) cannot receive the sent data from the BSW-ECU (master)" when the scan tool (M.U.T.-IIISE) checks the periodically sent data from each ECU and cannot receive the BSW-ECU (master) data only.
 
 
TROUBLE JUDGMENT CONDITIONS
Scan tool (M.U.T.-IIISE) judges the trouble when the periodically sent data from BSW-ECU (master) cannot be received.
 
 
TROUBLESHOOTING HINTS
  • Damaged harness wires and connectors
  • Power supply circuit malfunction of the BSW-ECU (master)
  • Malfunction of the BSW-ECU (master)
  • Malfunction of the gateway-ECU
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Connector check: gateway-ECU connector and BSW-ECU (master) connector.
cautionThe strand end of the twist wire should be within 10 cm (3.9 inches) from the connector. For details refer to .
Is the check result normal?
Go to Step 2.
Repair the defective connector. Replace the connector as necessary.
 
STEP 2. Resistance measurement at gateway-ECU connector and 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 .
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
(1) Disconnect the gateway-ECU connector and the BSW-ECU (master) connector, and measure at the wiring harness side.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Continuity between gateway-ECU connector terminal No. 19 and BSW-ECU (master) connector terminal No. 4
OK: The resistance should be 2 ohms or less
(5) Continuity between gateway-ECU connector terminal No. 18 and BSW-ECU (master) connector terminal No. 9
OK: The resistance should be 2 ohms or less
Is the check result normal?
<All the resistances measure 2 ohms or less> Go to Step 3 .
: <Either or all of the resistances measure more than 2 ohms> Check the intermediate connector C-147 and D-16, and repair if necessary. If the intermediate connector is in good condition, repair wiring harness between gateway-ECU connector and the BSW-ECU (master) connector.
 
STEP 3. Resistance measurement at gateway-ECU connector (short to ground check)
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
(1) Disconnect the gateway-ECU connector and BSW-ECU (master) connector and measure at the wiring harness side.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Measure the resistance between gateway-ECU connector terminal No. 19 and body ground. <CAN_H>
OK: 1 kΩ or more
(5) Measure the resistance between gateway-ECU connector terminal No. 18 and body ground. <CAN_L>
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 4 .
<Less than 1 kΩ> Check the intermediate connector C-147 and D-16, and repair if necessary. If the intermediate connector is in good condition, repair wiring harness between the gateway-ECU connector and BSW-ECU (master) connector.
 
STEP 4. Voltage measurement at gateway-ECU connector (short to power supply check) caution
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
cautionStrictly observe the specified wiring harness repair procedure. 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 battery terminal, and turn the ignition switch to the "ON" position.
(3) Measure the voltage between gateway-ECU connector terminal No. 19 and body ground. <CAN_H>
OK: 1.0 volt or less
(4) Measure the voltage between gateway-ECU connector terminal No. 18 and body ground. <CAN_L>
OK: 1.0 volt or less
Is the check result normal?
<1.0 volt or less> Go to Step 5.
<More than 1.0 volt> Check the intermediate connector C-147 and D-16, and repair if necessary. If the intermediate connector is in good condition, repair wiring harness between the gateway-ECU connector and BSW-ECU (master) connector.
 
STEP 5. Resistance measurement at gateway-ECU connector (line-to-line short check)
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
(1) Disconnect the gateway-ECU connector and BSW-ECU (master) connector and measure at the wiring harness side.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Measure the resistance between gateway-ECU connector terminal Nos.18 and 19.
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 6.
<Less than 1 kΩ> Check the intermediate connector C-147 and D-16, and repair if necessary. If the intermediate connector is in good condition, repair wiring harness between the gateway-ECU connector and BSW-ECU (master) connector.
 
STEP 6. Resistance measurement at gateway-ECU connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the gateway-ECU, and measure at the equipment side.
(2) Resistance at gateway-ECU connector terminal Nos.19 and 18
OK: 120 ± 20 ohms
Is the check result normal?
<Within 120 ± 20 ohms> Go to Step 7.
<Not within 120 ± 20 ohms> Replace the gateway-ECU.
 
STEP 7. Resistance measurement at BSW-ECU (master) connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the BSW-ECU (master), and measure at the equipment side.
(2) Resistance at BSW-ECU (master) connector terminal Nos. 4 and 9
OK: 120 ± 20 ohms
Is the check result normal?
<Within 120 ± 20 ohms> The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
<Not within 120 ± 20 ohms> Replace the BSW-ECU (master).