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Home >> Lexus >> 2024 >> TX 350 Base, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Meter / Gauge System - Diagnostic Codes & Symptom Tests (1 Of 2) >> Meter / Gauge System >> DTC B1512-87: Lost Communication with Steering Switch Control Module Missing Message; DTC B1513-87: Lost Communication with Steering Switch Control Module (Multiplex Switch)Missing Message [09/2023 - ] >> Procedure

DTC B1512-87: Lost Communication with Steering Switch Control Module Missing Message; DTC B1513-87: Lost Communication with Steering Switch Control Module (Multiplex Switch)Missing Message [09/2023 - ]: Procedure

  1. CONFIRM MODEL 
    1. Choose the model to be inspected.

      Result

      Result Proceed to
      w/ Touch Tracer Operation A
      w/o Touch Tracer Operation B

    Result: 

    B 

    See step  26

    Result: 

    A 

    See step  2

  2. CHECK FOR DTC 
    1. Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      Result

      Result Proceed to
      Only B1512-87 is output A
      Only B1513-87 is output B
      B1512-87 and B1513-87 are output C

    Result: 

    B 

    See step  11

    Result: 

    C 

    See step  19

    Result: 

    A 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 

    Pre-procedure1

    • Disconnect the D21 spiral cable sub-assembly connector.
    • Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition Result
      D21-4 (BHT) - Body ground Ignition switch off 11 to 14 V V

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      D21-2 (EHT) - Body ground Always Below 1 Ω Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - COMBINATION METER ASSEMBLY) 

    Pre-procedure1

    • Disconnect the D21 spiral cable sub-assembly connector.
    • Disconnect the D16 combination meter assembly connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      D21-1 (LIN) - D5-10 (CXPI) Always Below 1 Ω Ω
      D21-1 (LIN) - D16-32 (CXPI) Always Below 1 Ω Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. INSPECT SPIRAL CABLE SUB-ASSEMBLY 

    Refer to INSPECTION [09/2023 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  REMOVAL [09/2023 - 12/2023]  , or refer to  REMOVAL [12/2023 - ] 

    Result: 

    OK 

    See step  7

  7. CLEAR DTC 
    1. Clear the DTCs.

      Body Electrical > Combination Meter > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  8. CHECK FOR DTC 

    Pre-procedure1

    • Connect the spiral cable sub-assembly connectors.
    • Connect the D16 combination meter assembly connector.
    • Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      Result

      Result Proceed to
      B1512-87 is output A
      B1512-87 is not output B

    Post-procedure1

    • None

    Result: 

    B 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2023 - ] 

    Result: 

    A 

    See step  9

  9. CLEAR DTC 
    1. Clear the DTCs.

      Body Electrical > Combination Meter > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  10

  10. CHECK FOR DTC 

    Pre-procedure1

    • Disconnect the D21 and D5 spiral cable sub-assembly connectors.
    • Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      HINT: 

      When the combination meter assembly is operating normally and the D21 and D5 spiral cable sub-assembly connectors are disconnected, DTC B1512-87 or B1513-87 is stored.

      Result

      Result Proceed to
      B1512-87 and B1513-87 are output A
      Only B1512-87 is output B
      B1512-87 and B1513-87 are not output C

    Post-procedure1

    • None

    Result: 

    A 

    REPLACE MULTIPLEX NETWORK STEERING ECU. Refer to  REMOVAL [09/2023 - 12/2023]  , or refer to  REMOVAL [12/2023 - ] 

    Result: 

    B 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [09/2023 - ] 

    Result: 

    C 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [09/2023 - ] 

  11. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 

    Pre-procedure1

    • Disconnect the D5 spiral cable sub-assembly connector.
    • Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition Result
      D5-12 (+BA) - Body ground Ignition switch ON 11 to 14 V V

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      D5-4 (EAU) - Body ground Always Below 1 Ω Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - COMBINATION METER ASSEMBLY) 

    Pre-procedure1

    • Disconnect the D21 spiral cable sub-assembly connector.
    • Disconnect the D16 combination meter assembly connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      D5-10 (CXPI) - D21-1 (LIN) Always Below 1 Ω Ω
      D5-10 (CXPI) - D16-32 (CXPI) Always Below 1 Ω Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  14

  14. INSPECT SPIRAL CABLE SUB-ASSEMBLY 

    Refer to INSPECTION [09/2023 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  REMOVAL [09/2023 - 12/2023]  , or refer to  REMOVAL [12/2023 - ] 

    Result: 

    OK 

    See step  15

  15. CLEAR DTC 
    1. Clear the DTCs.

      Body Electrical > Combination Meter > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  16

  16. CHECK FOR DTC 

    Pre-procedure1

    • Connect the spiral cable sub-assembly connectors.
    • Connect the D16 combination meter assembly connector.
    • Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      Result

      Result Proceed to
      B1513-87 is output A
      B1513-87 is not output B

    Post-procedure1

    • None

    Result: 

    B 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2023 - ] 

    Result: 

    A 

    See step  17

  17. CLEAR DTC 
    1. Clear the DTCs.

      Body Electrical > Combination Meter > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  18

  18. CHECK FOR DTC 

    Pre-procedure1

    • Disconnect the D21 and D5 spiral cable sub-assembly connectors.
    • Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      HINT: 

      When the combination meter assembly is operating normally and the D21 and D5 spiral cable sub-assembly connectors are disconnected, DTC B1512-87 or B1513-87 is stored.

      Result

      Result Proceed to
      B1512-87 and B1513-87 are output A
      Only B1513-87 is output B
      B1512-87 and B1513-87 are not output C

    Post-procedure1

    • None

    Result: 

    A 

    REPLACE STEERING PAD SWITCH ASSEMBLY. Refer to  REMOVAL [09/2023 - ] 

    Result: 

    B 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [09/2023 - ] 

    Result: 

    C 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [09/2023 - ] 

  19. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - COMBINATION METER ASSEMBLY) 

    Pre-procedure1

    • Disconnect the D21 and D5 spiral cable sub-assembly connectors.
    • Disconnect the D16 combination meter assembly connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      D21-1 (LIN) - D16-32 (CXPI) Always Below 1 Ω Ω
      D5-10 (CXPI) - D16-32 (CXPI) Always Below 1 Ω Ω
      D21-1 (LIN), D5-10 (CXPI) or D16-32 (CXPI) - Body ground Always 10 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  20

  20. CLEAR DTC 
    1. Clear the DTCs.

      Body Electrical > Combination Meter > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  21

  21. CHECK FOR DTC 

    Pre-procedure1

    • Connect the D21 and D5 spiral cable sub-assembly connectors.
    • Connect the D16 combination meter assembly connector.
    • Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      Result

      Result Proceed to
      B1512-87 and B1513-87 are output A
      B1512-87 and B1513-87 are not output B

    Post-procedure1

    • None

    Result: 

    B 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2023 - ] 

    Result: 

    A 

    See step  22

  22. CLEAR DTC 
    1. Clear the DTCs.

      Body Electrical > Combination Meter > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  23

  23. CHECK FOR DTC 

    Pre-procedure1

    • Disconnect the D21 spiral cable sub-assembly connector.
    • Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      HINT: 

      • Even when the multiplex network steering ECU is operating normally and the D21 spiral cable sub-assembly connector is disconnected, as there are no changes in DTC output, DTC B1512-87 or B1513-87 remains stored.
      • If the multiplex network steering ECU is malfunctioning and the D21 spiral cable sub-assembly connector is disconnected, only DTC B1512-87 is stored.

      Result

      Result Proceed to
      B1512-87 and B1513-87 are output A
      Only B1512-87 is output B
      B1512-87 and B1513-87 are not output C

    Post-procedure1

    • None

    Result: 

    B 

    REPLACE MULTIPLEX NETWORK STEERING ECU. Refer to  REMOVAL [09/2023 - 12/2023]  , or refer to  REMOVAL [12/2023 - ] 

    Result: 

    C 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [09/2023 - ] 

    Result: 

    A 

    See step  24

  24. CLEAR DTC 
    1. Clear the DTCs.

      Body Electrical > Combination Meter > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  25

  25. CHECK FOR DTC 

    Pre-procedure1

    • Connect the D21 spiral cable sub-assembly connector.
    • Disconnect the D5 spiral cable sub-assembly connector.
    • Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      HINT: 

      • Even when the steering pad switch assembly is operating normally and the D5 spiral cable sub-assembly connector is disconnected, as there are no changes in DTC output, DTC B1512-87 or B1513-87 remains stored.
      • If the steering pad switch assembly is malfunctioning and the D5 spiral cable sub-assembly connector is disconnected, only DTC B1513-87 is stored.

      Result

      Result Proceed to
      B1512-87 and B1513-87 are output A
      Only B1512-87 is output B
      B1512-87 and B1513-87 are not output C

    Post-procedure1

    • None

    Result: 

    A 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [09/2023 - ] 

    Result: 

    B 

    REPLACE STEERING PAD SWITCH ASSEMBLY. Refer to  REMOVAL [09/2023 - ] 

    Result: 

    C 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [09/2023 - ] 

  26. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 

    Pre-procedure1

    • Disconnect the D21 spiral cable sub-assembly connector.
    • Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition Result
      D21-4 (BHT) - Body ground Ignition switch off 11 to 14 V V

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  27

  27. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      D21-2 (EHT) - Body ground Always Below 1 Ω Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  28

  28. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - COMBINATION METER ASSEMBLY) 

    Pre-procedure1

    • Disconnect the D16 combination meter assembly connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      D21-1 (LIN) - D16-32 (CXPI) Always Below 1 Ω Ω
      D21-1 (LIN) or D16-32 (CXPI) - Body ground Always 10 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  29

  29. INSPECT SPIRAL CABLE SUB-ASSEMBLY 

    Refer to INSPECTION [09/2023 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  REMOVAL [09/2023 - 12/2023]  , or refer to  REMOVAL [12/2023 - ] 

    Result: 

    OK 

    See step  30

  30. REPLACE MULTIPLEX NETWORK STEERING ECU 
    1. Replace the multiplex network steering ECU with a new or known good one.

      HINT: 

      Refer to REMOVAL [09/2023 - 12/2023] , or refer to REMOVAL [12/2023 - ]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  31

  31. CLEAR DTC 
    1. Clear the DTCs.

      Body Electrical > Combination Meter > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  32

  32. CHECK FOR DTC 
    1. Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      Result

      Result  Proceed to
      B1512-87 is not output A
      B1512-87 is output B

    Result: 

    A 

    END (MULTIPLEX NETWORK STEERING ECU IS DEFECTIVE) 

    Result: 

    B 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [09/2023 - ] 

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