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Home >> Lexus >> 2020 >> UX 200 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 50 (Can Communication System (Symptom Tests) (3 Of 3) (Hybrid)) >> CAN COMMUNICATION SYSTEM (for HV Model) >> Check Bus 4 Lines for Short Circuit [10/2018 - 08/2021] >> Procedure

Check Bus 4 Lines for Short Circuit [10/2018 - 08/2021]: Procedure

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  1. CHECK FOR SHORT IN CAN BUS LINES (NO. 7 CAN JUNCTION CONNECTOR) 
    1. Disconnect the cable from the negative (-) auxiliary battery terminal.
    2. Disconnect the No. 7 CAN junction connector.
    3. Measure the resistance according to the value(s) in the table below.
      GTY781718Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 7 CAN Junction Connector)      		 *b to No. 4 CAN Junction Connector
      *c to Central Gateway ECU (Network Gateway ECU) *d to Hybrid Vehicle Control ECU
      *e to Tire Pressure ECU and Receiver *f to ECM
      *g to Occupant Detection ECU *h to Brake Booster with Master Cylinder Assembly
      *i to Brake Actuator Assembly - -

      Standard Resistance

      Tester Connection Condition Specified Condition Connected to
      F94-1 (CANH) - F94-11 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 4 CAN junction connector
      F94-2 (CANH) - F94-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Central Gateway ECU (Network Gateway ECU)
      F94-3 (CANH) - F94-13 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Hybrid vehicle control ECU
      F94-4 (CANH) - F94-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Tire Pressure ECU and Receiver
      F94-5 (CANH) - F94-15 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher ECM
      F94-6 (CANH) - F94-16 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Occupant Detection ECU
      F94-7 (CANH) - F94-17 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Brake Booster with Master Cylinder Assembly
      F94-9 (CANH) - F94-19 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Brake Actuator Assembly

      Result

      Result Proceed to
      OK A
      NG (Line to central gateway ECU (network gateway ECU)) B
      NG (Line to No. 4 CAN junction connector) C
      NG (Line to ECU or sensor) D

    Result: 

    A 

    REPLACE NO. 7 CAN JUNCTION CONNECTOR 

    Result: 

    C 

    See step  3

    Result: 

    D 

    See step  5

    Result: 

    B 

    See step  2

  2. CHECK FOR SHORT IN CAN BUS LINES (NO. 7 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) 
    1. Disconnect the F61 central gateway ECU (network gateway ECU) connector.
    2. Measure the resistance according to the value(s) in the table below.
      GTY781690Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 7 CAN Junction Connector)      		 *b to Central Gateway ECU (Network Gateway ECU)

      Standard Resistance

      Tester Connection Condition Specified Condition
      F94-2 (CANH) - F94-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher

      Result

      Proceed to 
      OK
      NG

    Result: 

    OK 

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU). Refer to  REMOVAL [10/2018 - 07/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) 

  3. CHECK FOR SHORT IN CAN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR) 
    1. Reconnect the F94 No. 7 CAN junction connector.
    2. Disconnect the No. 4 CAN junction connector.
    3. Measure the resistance according to the value(s) in the table below.
      GTY820099Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 4 CAN Junction Connector)      		 *b to No. 7 CAN Junction Connector
      *c to Airbag ECU Assembly *d to Power Steering ECU with Motor Assembly
      *e to Steering Sensor - -

      Standard Resistance

      Tester Connection Condition Specified Condition Connected to
      F89-5 (CANH) - F89-16 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 7 CAN junction connector
      F89-6 (CANH) - F89-17 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Airbag ECU Assembly
      F89-7 (CANH) - F89-18 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Power Steering ECU with Motor Assembly
      F89-8 (CANH) - F89-19 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Steering Sensor

      Result

      Result Proceed to
      OK A
      NG (Line to No. 7 CAN junction connector) B
      NG (Line to Airbag ECU assembly) C
      NG (Line to ECU or sensor) D

    Result: 

    A 

    REPLACE NO. 4 CAN JUNCTION CONNECTOR 

    Result: 

    B 

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 7 CAN JUNCTION CONNECTOR) 

    Result: 

    D 

    See step  5

    Result: 

    C 

    See step  4

  4. CHECK FOR SHORT IN CAN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR - AIRBAG ECU ASSEMBLY) 
    1. Disconnect the F57 airbag ECU assembly connector.
    2. Measure the resistance according to the value(s) in the table below.
      GTY820091Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 4 CAN Junction Connector)      		 *b to Airbag ECU Assembly

      Standard Resistance

      Tester Connection Condition Specified Condition
      F89-6 (CANH) - F89-17 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL [10/2018 - 07/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - AIRBAG ECU ASSEMBLY) 

  5. CHECK FOR SHORT IN CAN BUS LINES (ECU OR SENSOR) 
    1. Reconnect all wire harness connectors.
    2. Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short circuited branch line is connected.

      Refer to TERMINALS OF ECU [10/2018 - 10/2019] , or refer to TERMINALS OF ECU [10/2019 - 08/2021]

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      F61-22 (CA2H) - F61-7 (CA2L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω
      GTY811814Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Central Gateway ECU (Network Gateway ECU))

      HINT: 

      • If the resistance becomes normal (between 54 and 69 Ω) when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.
      • If the resistance does not become normal when the connector is disconnected from the ECU or sensor, check for a short in the wire harness and repair or replace the wire harness or connector if necessary.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECU OR SENSOR 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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