OCCUPANT CLASSIFICATION SYSTEM, 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 auxiliary battery positive line.

DTC No. DTC Detections Conditions Trouble Areas
B1794

  • The occupant detection ECU receives an open circuit signal in the occupant detection ECU auxiliary battery positive line.

  • Occupant detection ECU malfunction

  • Auxiliary battery

  • Wire harness

  • Occupant detection ECU

Tech Tips

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

WIRING DIAGRAM

A011WLSE05

INSPECTION PROCEDURE

Note

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

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

PROCEDURE

  1. CHECK AUXILIARY BATTERY VOLTAGE

    1. Measure the voltage of the auxiliary battery.

      Standard Voltage
      11 to 14 V
    NG

    INSPECT CHARGING SYSTEM AND AUXILIARY BATTERY Click here

    OK

  2. CHECK WIRE HARNESS (SOURCE VOLTAGE)

    1. Turn the power switch off.

      A011VCWE02

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

    3. Disconnect the connector from the occupant detection ECU.

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

    5. Turn the power 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 Power switch off 11 to 14 V

    7. Turn the power 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
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Occupant Detection ECU)
    NG

    REPLACE WIRE HARNESS

    OK

  3. CHECK DTC

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

    2. Connect the connector to the occupant detection ECU.

    3. Connect the cable to the negative (-) auxiliary 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 power switch off.

    7. Turn the power 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 power 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 (-) auxiliary battery terminal.

    2. Replace the occupant detection ECU Click here.

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

    NEXT

  5. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK

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

    NEXT

    END