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DTC U1171-87: Lost Communication with Brake System Control Module (ch3) Missing Message [03/2024 - ]: Procedure

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  1. CHECK FOR OPEN IN CAN MAIN BUS LINES 
    1. Disconnect the cable from the negative (-) auxiliary battery terminal.
    2. Measure the resistance according to the value(s) in the table below.
      GTY1254312Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (No. 7 CAN Junction Connector)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-1 (CANH) - G65-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal Below 70 Ω

      Result

      Result
      OK
      NG

    Result: 

    NG 

    See step  23

    Result: 

    OK 

    See step  2

  2. CHECK FOR SHORT IN CAN BUS LINES 
    1. Measure the resistance according to the value(s) in the table below.
      GTY1254312Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (No. 7 CAN Junction Connector)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-1 (CANH) - G65-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 54 Ω or higher

      Result

      Result
      OK
      NG

    Result: 

    NG 

    See step  17

    Result: 

    OK 

    See step  3

  3. CHECK FOR SHORT TO +B IN CAN BUS LINE 
    1. Measure the resistance according to the value(s) in the table below.
      GTY1254471Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 DLC3 - -
      *a Component with harness connected
      (No. 7 CAN junction connector)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-1 (CANH) - D66-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      G65-12 (CANL) - D66-16 (BAT)

      Result

      Result
      OK
      NG

    Result: 

    NG 

    See step  11

    Result: 

    OK 

    See step  4

  4. CHECK FOR SHORT TO GND IN CAN BUS LINE 
    1. Measure the resistance according to the value(s) in the table below.
      GTY1254472Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 DLC3 - -
      *a Component with harness connected
      (No. 7 CAN junction connector)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-1 (CANH) - D66-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      G65-12 (CANL) - D66-4 (CG)

      Result

      Result
      OK
      NG

    Result: 

    OK 

    INSPECT FOR INTERMITTENT PROBLEMS. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - ] 

    Result: 

    NG 

    See step  5

  5. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 
    1. Disconnect the G65 No. 7 CAN junction connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-1 (CANH) - D66-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      G65-12 (CANL) - D66-4 (CG)

      Result

      Result
      OK
      NG

    Result: 

    NG 

    See step  8

    Result: 

    OK 

    See step  6

  6. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - ABSORBER CONTROL ECU) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-3 (CANH) - D66-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      G65-14 (CANL) - D66-4 (CG)

      Result

      Result
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  7

  7. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-2 (CANH) - D66-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      G65-13 (CANL) - D66-4 (CG)

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 7 CAN JUNCTION CONNECTOR 

    Result: 

    NG 

    See step  10

  8. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 
    1. Disconnect the A38 No. 2 skid control ECU (brake actuator assembly) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-1 (CANH) - D66-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      G65-12 (CANL) - D66-4 (CG)

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 

  9. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - ABSORBER CONTROL ECU) 
    1. Disconnect the G2 absorber control ECU connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-3 (CANH) - D66-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      G65-14 (CANL) - D66-4 (CG)

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE ABSORBER CONTROL ECU. Refer to  REMOVAL [03/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - ABSORBER CONTROL ECU) 

  10. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL) 
    1. Disconnect the G66 No. 2 CAN junction terminal connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-2 (CANH) - D66-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      G65-13 (CANL) - D66-4 (CG)

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 CAN JUNCTION TERMINAL 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL) 

  11. CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 
    1. Disconnect the G65 No. 7 CAN junction connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-1 (CANH) - D66-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      G65-12 (CANL) - D66-16 (BAT)

      Result

      Result
      OK
      NG

    Result: 

    NG 

    See step  14

    Result: 

    OK 

    See step  12

  12. CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - ABSORBER CONTROL ECU) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-3 (CANH) - D66-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      G65-14 (CANL) - D66-16 (BAT)

      Result

      Result
      OK
      NG

    Result: 

    NG 

    See step  15

    Result: 

    OK 

    See step  13

  13. CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-2 (CANH) - D66-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      G65-13 (CANL) - D66-16 (BAT)

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 7 CAN JUNCTION CONNECTOR 

    Result: 

    NG 

    See step  16

  14. CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 
    1. Disconnect the A38 No. 2 skid control ECU (brake actuator assembly) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-1 (CANH) - D66-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      G65-12 (CANL) - D66-16 (BAT)

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 

  15. CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - ABSORBER CONTROL ECU) 
    1. Disconnect the G2 absorber control ECU connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-3 (CANH) - D66-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      G65-14 (CANL) - D66-16 (BAT)

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE ABSORBER CONTROL ECU. Refer to  REMOVAL [03/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - ABSORBER CONTROL ECU) 

  16. CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL) 
    1. Disconnect the G66 No. 2 CAN junction terminal connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-2 (CANH) - D66-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      G65-13 (CANL) - D66-16 (BAT)

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 CAN JUNCTION TERMINAL 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL) 

  17. CHECK FOR SHORT IN CAN BUS LINES (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 
    1. Disconnect the G65 No. 7 CAN junction connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-1 (CANH) - G65-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

      Result
      OK
      NG

    Result: 

    NG 

    See step  20

    Result: 

    OK 

    See step  18

  18. CHECK FOR SHORT IN CAN BUS LINES (NO. 7 CAN JUNCTION CONNECTOR - ABSORBER CONTROL ECU) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-3 (CANH) - G65-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      Result

      Result
      OK
      NG

    Result: 

    NG 

    See step  21

    Result: 

    OK 

    See step  19

  19. CHECK FOR SHORT IN CAN BUS LINES (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-2 (CANH) - G65-13 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 7 CAN JUNCTION CONNECTOR 

    Result: 

    NG 

    See step  22

  20. CHECK FOR SHORT IN CAN BUS LINES (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 
    1. Disconnect the A38 No. 2 skid control ECU (brake actuator assembly) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-1 (CANH) - G65-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 

  21. CHECK FOR SHORT IN CAN BUS LINES (NO. 7 CAN JUNCTION CONNECTOR - ABSORBER CONTROL ECU) 
    1. Disconnect the G2 absorber control ECU connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-3 (CANH) - G65-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE ABSORBER CONTROL ECU. Refer to  REMOVAL [03/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - ABSORBER CONTROL ECU) 

  22. CHECK FOR SHORT IN CAN BUS LINES (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL) 
    1. Disconnect the G66 No. 2 CAN junction terminal connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-2 (CANH) - G65-13 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 CAN JUNCTION TERMINAL 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL) 

  23. CHECK FOR OPEN IN CAN MAIN BUS LINES (NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 
    1. Disconnect the A38 No. 2 skid control ECU (brake actuator assembly) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A38-28 (CA3H) - A38-44 (CA3L) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    See step  24

  24. CHECK FOR OPEN IN CAN MAIN BUS LINES (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 
    1. Reconnect the A38 No. 2 skid control ECU (brake actuator assembly) connector.
    2. Disconnect the G65 No. 7 CAN junction connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-1 (CANH) - G65-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

      Result
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)) 

    Result: 

    OK 

    See step  25

  25. CHECK FOR OPEN IN CAN MAIN BUS LINES (NO. 7 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION TERMINAL) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G65-2 (CANH) - G65-13 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 7 CAN JUNCTION CONNECTOR 

    Result: 

    NG 

    See step  26

  26. CHECK FOR OPEN IN CAN MAIN BUS LINES (NO. 2 CAN JUNCTION TERMINAL) 
    1. Reconnect the G65 No. 7 CAN junction connector.
    2. Disconnect the G66 No. 2 CAN junction terminal connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G66-3 (CANH) - G66-2 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

      Result
      OK
      NG

    Result: 

    OK 

    REPLACE NO. 2 CAN JUNCTION TERMINAL 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 2 CAN JUNCTION TERMINAL - NO. 7 CAN JUNCTION CONNECTOR) 

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