OCCUPANT CLASSIFICATION SYSTEM (for TMMK Made), Diagnostic DTC:B1794

DTC Code DTC Name
B1794 Open in Occupant Classification ECU Battery Positive Line

DESCRIPTION

DTC B1794 is stored when a malfunction is detected in the occupant detection ECU battery positive line.

DTC No. DTC Detections Conditions Trouble Areas
B1794

  • The occupant detection ECU detects an open in the occupant detection ECU battery positive line.

  • Occupant detection ECU malfunction

  • Battery

  • Wire harness

  • Occupant detection ECU

WIRING DIAGRAM

B000KP4E13

INSPECTION PROCEDURE

Note


  • After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work Click here.

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check for DTCs stored in the occupant detection ECU. When DTC B1794 is output, perform troubleshooting for the DTC.

PROCEDURE


  1. CHECK BATTERY VOLTAGE


    1. Measure the voltage of the battery.

      Standard Voltage
      11 to 14 V

    NG

    INSPECT CHARGING SYSTEM AND BATTERY Click here

    OK

  2. CHECK WIRE HARNESS (SOURCE VOLTAGE)


    1. B000H67E02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Occupant Detection ECU)

      Turn the engine switch off.

    2. Disconnect the cable from the negative (-) battery terminal.

    3. Disconnect the connector from the occupant detection ECU.

    4. Connect the cable to the negative (-) battery terminal.

    5. Turn the engine switch on (IG).

    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      d11-1 (+B) - Body ground Always 11 to 14 V

    7. Turn the engine switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      d11-3 (GND) - Body ground Always Below 1 Ω

    NG

    REPLACE WIRE HARNESS

    OK

  3. CHECK DTC


    1. Disconnect the cable from the negative (-) battery terminal.

    2. Connect the connector to the occupant detection ECU.

    3. Connect the cable to the negative (-) battery terminal.

    4. Clear the DTCs stored in the occupant detection ECU Click here.

    5. Clear the DTCs stored in the airbag sensor assembly Click here.

    6. Turn the engine switch off.

    7. Turn the engine switch on (IG), and wait for at least 10 seconds.

    8. Check for DTCs Click here.

      OK
      DTC B1794 is not output.

      Tech Tips

      Codes other than DTC B1794 may be output at this time, but they are not related to this check.

    9. Turn the engine switch off.


    NG

    REPLACE OCCUPANT DETECTION ECU Click here

    OK

    USE SIMULATION METHOD TO CHECK Click here

  4. REPLACE OCCUPANT DETECTION ECU


    1. Disconnect the cable from the negative (-) battery terminal.

    2. Replace the occupant detection ECU Click here.

    3. Connect the cable to the negative (-) battery terminal.


    NEXT

  5. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK


    1. Using the GTS, perform Zero Point Calibration and Sensitivity Check Click here.


    NEXT

    END