LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2019 >> LS 500 Base, AWD >> Repair and Diagnosis (Single Page) >> Restraints >> Air Bag, SRS >> Occupant Classification System - Diagnostic Codes & Symptom Tests >> Occupant Classification System >> LIN Communication Circuit [10/2023 - ] >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

LIN Communication Circuit [10/2023 - ]: Procedure

  1. CHECK ERROR CODE 
    1. Check the Error Code.

      Result

      Result  Proceed to
      Error code 17 is output A
      Error code 18 is output B
      Error code 17 and 18 are output C

    Result: 

    B 

    See step  7

    Result: 

    C 

    See step  12

    Result: 

    A 

    See step  2

  2. CHECK CONNECTORS 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 60 seconds.
    3. Check that the connectors are properly connected to the airbag ECU assembly and front seat adjuster assembly RH (front occupant classification sensor LH).

      Result

      Result  Proceed to
      Connectors are properly connected A
      Connectors are not properly connected B

    Result: 

    B 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    A 

    See step  3

  3. CHECK CONNECTION OF CONNECTORS 
    1. Disconnect the airbag ECU assembly connector.
      GTY984871Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Adjuster Assembly RH (Front Occupant Classification Sensor LH)
      *2 Airbag ECU Assembly
      *3 Wire Harness
    2. Disconnect the front seat adjuster assembly RH (front occupant classification sensor LH) connector.
    3. Check that the connectors (on the airbag ECU assembly side and front seat adjuster assembly RH (front occupant classification sensor LH) side) are not damaged.

      Result

      Result  Proceed to
      Connectors are not deformed or damaged A
      Connectors are deformed or damaged B

    Result: 

    B 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - FRONT SEAT ADJUSTER ASSEMBLY RH) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L64-24 (SVC) - Q43-1 Always Below 1 Ω
      L64-32 (SIG) - Q43-2 Always Below 1 Ω
      L64-31 (SGD) - Q43-3 Always Below 1 Ω
      GTY1229879Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Adjuster Assembly RH
      *2 Airbag ECU Assembly
      *3 Wire Harness
      *a Front view of wire harness connector
      (to Airbag ECU Assembly)
      *b Front view of wire harness connector
      (to Front Seat Adjuster Assembly RH (Front Occupant Classification Sensor LH))

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. REPLACE FRONT SEAT ADJUSTER ASSEMBLY RH 
    1. Replace the front seat adjuster assembly RH with a new one.

      Refer to DISASSEMBLY [10/2023 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  6

  6. PERFORM ZERO POINT CALIBRATION 
    1. Using the GTS, perform "Occupant Detection Sensor Zero Point Calibration".

      Refer to INITIALIZATION [10/2023 - ]

      Body Electrical > SRS Airbag > Utility 

      Tester Display
      Occupant Detection Sensor Zero Point Calibration

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

  7. CHECK CONNECTORS 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 60 seconds.
    3. Check that the connectors are properly connected to the airbag ECU assembly and front seat adjuster assembly RH (rear occupant classification sensor LH).

      Result

      Result  Proceed to
      Connectors are properly connected A
      Connectors are not properly connected B

    Result: 

    B 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    A 

    See step  8

  8. CHECK CONNECTION OF CONNECTORS 
    1. Disconnect the airbag ECU assembly connector.
      GTY984871Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Adjuster Assembly RH (Rear Occupant Classification Sensor LH)
      *2 Airbag ECU Assembly
      *3 Wire Harness
    2. Disconnect the front seat adjuster assembly RH (rear occupant classification sensor LH) connector.
    3. Check that the connectors (on the airbag ECU assembly side and front seat adjuster assembly RH (rear occupant classification sensor LH) side) are not damaged.

      Result

      Result  Proceed to
      Connectors are not deformed or damaged A
      Connectors are deformed or damaged B

    Result: 

    B 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - FRONT SEAT ADJUSTER ASSEMBLY RH) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L64-24 (SVC) - Q44-1 Always Below 1 Ω
      L64-32 (SIG) - Q44-2 Always Below 1 Ω
      L64-31 (SGD) - Q44-3 Always Below 1 Ω
      GTY1239511Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Adjuster Assembly RH
      *2 Airbag ECU Assembly
      *3 Wire Harness
      *a Front view of wire harness connector
      (to Airbag ECU Assembly)
      *b Front view of wire harness connector
      (to Front Seat Adjuster Assembly RH (Rear Occupant Classification Sensor LH))

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  10

  10. REPLACE FRONT SEAT ADJUSTER ASSEMBLY RH 
    1. Replace the front seat adjuster assembly RH with a new one.

      Refer to DISASSEMBLY [10/2023 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  11

  11. PERFORM ZERO POINT CALIBRATION 
    1. Using the GTS, perform "Occupant Detection Sensor Zero Point Calibration".

      Refer to INITIALIZATION [10/2023 - ]

      Body Electrical > SRS Airbag > Utility 

      Tester Display
      Occupant Detection Sensor Zero Point Calibration

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

  12. CHECK CONNECTORS 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 60 seconds.
    3. Check that the connectors are properly connected to the airbag ECU assembly and front seat adjuster assembly RH.

      Result

      Result  Proceed to
      Connectors are properly connected A
      Connectors are not properly connected B

    Result: 

    B 

    CONNECT CONNECTORS PROPERLY 

    Result: 

    A 

    See step  13

  13. CHECK CONNECTION OF CONNECTORS 
    1. Disconnect the airbag ECU assembly connector.
      GTY985316Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Adjuster Assembly RH
      *2 Airbag ECU Assembly
      *3 Wire Harness
    2. Disconnect the front seat adjuster assembly RH connector.
    3. Check that the connectors (on the airbag ECU assembly side and front seat adjuster assembly RH side) are not damaged.

      Result

      Result  Proceed to
      Connectors are not deformed or damaged A
      Connectors are deformed or damaged B

    Result: 

    B 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  14

  14. CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - FRONT SEAT ADJUSTER ASSEMBLY RH) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L64-24 (SVC) - Q43-1 Always Below 1 Ω
      L64-24 (SVC) - Q44-1 Always Below 1 Ω
      L64-32 (SIG) - Q43-2 Always Below 1 Ω
      L64-32 (SIG) - Q44-2 Always Below 1 Ω
      L64-31 (SGD) - Q43-3 Always Below 1 Ω
      L64-31 (SGD) - Q44-3 Always Below 1 Ω
      GTY1236379Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Adjuster Assembly RH
      *2 Airbag ECU Assembly
      *3 Wire Harness
      *a Front view of wire harness connector
      (to Airbag ECU Assembly)
      *b Front view of wire harness connector
      (to Front Seat Adjuster Assembly RH (Front Occupant Classification Sensor LH))
      *c Front view of wire harness connector
      (to Front Seat Adjuster Assembly RH (Rear Occupant Classification Sensor LH))

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  15

  15. CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - FRONT SEAT ADJUSTER ASSEMBLY RH) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L64-32 (SIG) - Other terminals and body ground Always 10 kΩ or higher
      Q43-2 - Other terminals and body ground Always 10 kΩ or higher
      Q44-2 - Other terminals and body ground Always 10 kΩ or higher
      GTY1236380Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Adjuster Assembly RH
      *2 Airbag ECU Assembly
      *3 Wire Harness
      *a Front view of wire harness connector
      (to Airbag ECU Assembly)
      *b Front view of wire harness connector
      (to Front Seat Adjuster Assembly RH (Front Occupant Classification Sensor LH))
      *c Front view of wire harness connector
      (to Front Seat Adjuster Assembly RH (Rear Occupant Classification Sensor LH))

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  16

  16. CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - FRONT SEAT ADJUSTER ASSEMBLY RH) 
    1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
      GTY1236380Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front Seat Adjuster Assembly RH
      *2 Airbag ECU Assembly
      *3 Wire Harness
      *a Front view of wire harness connector
      (to Airbag ECU Assembly)
      *b Front view of wire harness connector
      (to Front Seat Adjuster Assembly RH (Front Occupant Classification Sensor LH))
      *c Front view of wire harness connector
      (to Front Seat Adjuster Assembly RH (Rear Occupant Classification Sensor LH))
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      L64-32 (SIG) - Body ground Engine switch on (IG) Below 1 V
      Q43-2 - Body ground Engine switch on (IG) Below 1 V
      Q44-2 - Body ground Engine switch on (IG) Below 1 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  17

  17. REPLACE AIRBAG ECU ASSEMBLY 
    1. Replace the airbag ECU assembly with a new one.

      Refer to REMOVAL [10/2023 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  18

  18. PERFORM ZERO POINT CALIBRATION 
    1. Using the GTS, perform "Occupant Detection Sensor Zero Point Calibration".

      Refer to INITIALIZATION [10/2023 - ]

      Body Electrical > SRS Airbag > Utility 

      Tester Display
      Occupant Detection Sensor Zero Point Calibration

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    END 

scientia non olet · About LEMON Manuals