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Home >> Lexus >> 2025 >> NX 250 FWD >> Repair and Diagnosis >> Electrical >> Gauges >> Meter / Gauge System - Diagnostic Codes (2 Of 2), Symptom Tests & Circuit Tests >> 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 [11/2021 - ] >> 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 [11/2021 - ]: 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

    1. Disconnect the D27 spiral cable sub-assembly connector.

      Procedure1

    2. Measure the voltage according to the value(s) in the table below.
      GTY1068056Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Spiral Cable Sub-assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      D27-4 (BHT) - Body ground Ignition switch off*1 11 to 14 V
      D27-4 (BHT) - Body ground Always*2 11 to 14 V
      1. *1: for HEV Model
      2. *2: for Gasoline Model

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. 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
      D27-2 (EHT) - Body ground Always Below 1 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

    1. Disconnect the D144 spiral cable sub-assembly connector.
    2. Disconnect the D21 combination meter assembly connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      D27-1 (LIN) - D144-10 (CXPI) Always Below 1 Ω
      D27-1 (LIN) - D21-32 (CXPI) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. INSPECT SPIRAL CABLE SUB-ASSEMBLY 

    Refer to INSPECTION [11/2021 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    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

    1. Connect the spiral cable sub-assembly connectors.
    2. Connect the D21 combination meter assembly connector.

      Procedure1

    3. 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

    4. None

    Result: 

    B 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - ] 

    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

    1. Disconnect the D27 and D144 spiral cable sub-assembly connectors.

      Procedure1

    2. Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      HINT: 

      When the combination meter assembly is operating normally and the D27 and D144 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

    3. None

    Result: 

    A 

    REPLACE MULTIPLEX NETWORK STEERING ECU. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    B 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    C 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

  11. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 

    Pre-procedure1

    1. Disconnect the D144 spiral cable sub-assembly connector.

      Procedure1

    2. Measure the voltage according to the value(s) in the table below.
      GTY1067716Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Spiral Cable Sub-assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      D144-12 (+BA) - Body ground Ignition switch ON 11 to 14 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. 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
      D144-4 (EAU) - Body ground Always Below 1 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

    1. Disconnect the D27 spiral cable sub-assembly connector.
    2. Disconnect the D21 combination meter assembly connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      D144-10 (CXPI) - D27-1 (LIN) Always Below 1 Ω
      D144-10 (CXPI) - D21-32 (CXPI) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  14

  14. INSPECT SPIRAL CABLE SUB-ASSEMBLY 

    Refer to INSPECTION [11/2021 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    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

    1. Connect the spiral cable sub-assembly connectors.
    2. Connect the D21 combination meter assembly connector.

      Procedure1

    3. 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

    4. None

    Result: 

    B 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - ] 

    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

    1. Disconnect the D27 and D144 spiral cable sub-assembly connectors.

      Procedure1

    2. Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      HINT: 

      When the combination meter assembly is operating normally and the D27 and D144 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

    3. None

    Result: 

    A 

    REPLACE STEERING PAD SWITCH ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    B 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    C 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

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

    Pre-procedure1

    1. Disconnect the D27 and D144 spiral cable sub-assembly connectors.
    2. Disconnect the D21 combination meter assembly connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      D27-1 (LIN) - D21-32 (CXPI) Always Below 1 Ω
      D144-10 (CXPI) - D21-32 (CXPI) Always Below 1 Ω
      D27-1 (LIN), D144-10 (CXPI) or D21-32 (CXPI) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    4. 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

    1. Connect the D27 and D144 spiral cable sub-assembly connectors.
    2. Connect the D21 combination meter assembly connector.

      Procedure1

    3. 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

    4. None

    Result: 

    B 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - ] 

    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

    1. Disconnect the D27 spiral cable sub-assembly connector.

      Procedure1

    2. Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      HINT: 

      • Even when the multiplex network steering ECU is operating normally and the D27 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 D27 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

    3. None

    Result: 

    B 

    REPLACE MULTIPLEX NETWORK STEERING ECU. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    C 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    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

    1. Connect the D27 spiral cable sub-assembly connector.
    2. Disconnect the D144 spiral cable sub-assembly connector.

      Procedure1

    3. Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      HINT: 

      • Even when the steering pad switch assembly is operating normally and the D144 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 D144 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 B1513-87 is output B
      B1512-87 and B1513-87 are not output C

      Post-procedure1

    4. None

    Result: 

    A 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    B 

    REPLACE STEERING PAD SWITCH ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    C 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

  26. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 

    Pre-procedure1

    1. Disconnect the D27 spiral cable sub-assembly connector.

      Procedure1

    2. Measure the voltage according to the value(s) in the table below.
      GTY1068056Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Spiral Cable Sub-assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      D27-4 (BHT) - Body ground Ignition switch off*1 11 to 14 V
      D27-4 (BHT) - Body ground Always*2 11 to 14 V
      1. *1: for HEV Model
      2. *2: for Gasoline Model

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. 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
      D27-2 (EHT) - Body ground Always Below 1 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

    1. Disconnect the D21 combination meter assembly connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      D27-1 (LIN) - D21-32 (CXPI) Always Below 1 Ω
      D27-1 (LIN) or D21-32 (CXPI) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    3. None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  29

  29. INSPECT SPIRAL CABLE SUB-ASSEMBLY 

    Refer to INSPECTION [11/2021 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    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 [11/2021 - ]

      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
      DTC B1512-87 is not output A
      DTC B1512-87 is output B

    Result: 

    A 

    END (MULTIPLEX NETWORK STEERING ECU IS DEFECTIVE) 

    Result: 

    B 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

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