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Home >> Toyota >> 2025 >> GR86 Base, Automatic Trans >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Meter / Gauge System - Diagnostic Codes, Circuit Tests & Symptom Tests >> Meter / Gauge System >> DTC B1502: Warning Box Communication Stop [10/2024 - ] >> Procedure

DTC B1502: Warning Box Communication Stop [10/2024 - ]: Procedure

  1. CHECK COMBINATION METER ASSEMBLY 
    1. Turn the ignition switch to ON, and make sure that the combination meter assembly operates properly.

      OK

      The combination meter activate normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO POWER SOURCE CIRCUIT 

    Refer to Power Source Circuit [11/2021 - ] 

    Result: 

    OK 

    See step  2

  2. CHECK MAP LIGHT ASSEMBLY (WARNING BOX) 
    1. Turn the ignition switch on and check if the warning light in the map light assembly (warning box) comes on.

      OK

      The map light assembly (warning box) activate normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  3

  3. CHECK FOR DTC 
    1. Check for DTCs.

      Body Electrical > Combination Meter > Trouble Codes 

      OK

      DTC B1502 (current code) is not output.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  4

  4. CHECK CONNECTOR 
    1. Turn the ignition switch off.
    2. Disconnect the k4 map light assembly (warning box) connector.
    3. Disconnect the F11 combination meter assembly connector.
    4. Check the condition of each connector.

      OK

      Each connector is normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK 

    HINT: 

    • Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

      Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - ]

    • In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.

    Result: 

    NG 

    REPAIR OR REPLACE THE POOR CONTACT OF CONNECTOR. 

  5. CHECK HARNESS AND CONNECTOR (MAP LIGHT ASSEMBLY (WARNING BOX) - COMBINATION METER ASSEMBLY) 
    1. Turn the ignition switch off.
    2. Disconnect the k4 map light assembly (warning box) connector.
    3. Disconnect the F11 combination meter assembly connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      k4-2 - F11-12(U-ART2 (WA-BOX)) Always Below 10 Ω
      k4-2 or F11-12(U-ART2 (WA-BOX)) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAP LAMP ASSEMBLY (WARNING BOX) 

    Refer to REMOVAL [11/2021 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  6. CHECK MAP LIGHT ASSEMBLY (WARNING BOX) POWER SOURCE CIRCUIT 
    1. Turn the ignition switch off.
    2. Disconnect the k4 map light assembly (warning box) connector.
    3. Turn the ignition switch to ON.
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      k4-3 - Body ground Always 10V or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAP LAMP ASSEMBLY (WARNING BOX) 

    Refer to REMOVAL [11/2021 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR