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Diagnostic Item 1: Communication with gateway-ECU is not possible [CAN-C (Diag)].
 
 
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 scan tool (M.U.T.-IIISE) receives data from the gateway-ECU via CAN-C (Diag) line.
 
 
TROUBLE JUDGMENT CONDITIONS
The scan tool (M.U.T.-IIISE) judges the trouble when the data from the gateway-ECU cannot be received.
 
 
TROUBLESHOOTING HINTS
  • Damaged harness wires and connectors
  • Malfunction of the gateway-ECU power supply circuit
  • Malfunction of the gateway-ECU
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Connector check: gateway-ECU connector and data link 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.
 
STEP 2. Continuity check between data link connector and gateway-ECU 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 scan tool (M.U.T.-IIISE) and gateway-ECU connector and measure at the wiring harness side.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
(3) Ensure that the negative battery terminal is disconnected.
(4) Check the continuity between data link connector terminal No. 6 and gateway-ECU connector terminal No. 29. <CAN_H>
OK: The resistance should be 2 ohms or less.
(5) Check the continuity between data link connector terminal No. 14 and gateway-ECU connector terminal No. 28. <CAN_L>
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> Repair the wiring harness between the data link connector and gateway-ECU connector.
 
STEP 3. Resistance measurement at data link 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 scan tool (M.U.T.-IIISE) and gateway-ECU connector and measure at the wiring harness side.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
(3) Ensure that the negative battery terminal is disconnected.
(4) Measure the resistance between data link connector terminal No. 6 and body ground. <CAN_H>
OK: 1 kΩ or more
(5) Measure the resistance between data link connector terminal No. 14 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> Repair the wiring harness between the data link connector and gateway-ECU connector.
 
STEP 4. Voltage measurement at data link connector (short to power supply 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 scan tool (M.U.T.-IIISE) and gateway-ECU 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 data link connector terminal No. 6 and body ground. <CAN_H>
OK: 1.0 volt or less
(4) Measure the voltage between data link connector terminal No. 14 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> Repair the wiring harness between the data link connector and gateway-ECU connector.
 
STEP 5. Resistance measurement at data link 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 scan tool (M.U.T.-IIISE) and gateway-ECU connector and measure at the wiring harness side.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
(3) Ensure that the negative battery terminal is disconnected.
(4) Measure the resistance between data link connector terminal Nos. 6 and 14.
OK: 1 kΩ or more
Is the check result normal?
<1 kΩ or more> Go to Step 6.
<Less than 1 kΩ> Repair the wiring harness between the data link connector and gateway-ECU connector.
 
STEP 6. Resistance measurement at gateway-ECU connector
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
cautionA digital multimeter should be used. For details refer to .
(1) Remove the gateway-ECU, and measure at the equipment side.
(2) Measure the resistance between gateway-ECU connector terminal Nos. 28 and 29.
OK: 60 ± 10 ohms
Is the check result normal?
<Within 60 ± 10 ohms> Power supply to the gateway-ECU may be suspected (Refer to ).
<Not within 60 ± 10 ohms> Replace the gateway-ECU (Refer to <From 22 Model year>).