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.

DTC No. Detection Item DTC Detection Condition Trouble Area
B1794 Open in Occupant Classification ECU Battery Positive Line

    One of the following conditions is met:

  • Occupant detection ECU circuit malfunction.

  • Occupant detection ECU malfunction.

  • Harness or connector

  • Occupant detection ECU

Tech Tips


  • When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1794 of the occupant classification system.

  • Use the GTS to check for DTCs of the occupant detection ECU, otherwise the DTCs cannot be read.

WIRING DIAGRAM

A01HGUTE12
*a from Battery
*b from IG2-MAIN Relay
*c A/BAG
*d Occupant Detection ECU

CAUTION / NOTICE / HINT

Note


  • When disconnecting the cable, some systems need to be initialized after the cable is reconnected.

    Click here

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

  • If troubleshooting (wire harness inspection) is difficult to perform, remove the frontseat RH installation bolts to see the undersurface of the seat cushion.

PROCEDURE


  1. CHECK DTC


    1. Turn the engine switch on (IG), and wait for at least 60 seconds.

    2. Clear the DTCs.

      Click here


      Body Electrical > Occupant Detection > Clear DTCs

      Tech Tips


      • First clear the DTCs stored in the occupant detection ECU, and then clear the DTCs stored in the airbag ECU assembly.

      • Use the GTS to clear the DTCs of the occupant detection ECU, otherwise the DTCs cannot be cleared.

    3. Turn the engine switch off.

    4. Turn the engine switch on (IG), and wait for at least 60 seconds.

    5. Check for DTCs.

      Click here


      Body Electrical > Occupant Detection > Trouble Codes
      Result
      Proceed to
      DTC B1794 is not output
      DTC B1794 is output

      Tech Tips

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


    DTC B1794 is not output

    USE SIMULATION METHOD TO CHECK Click here

    DTC B1794 is output

  2. CHECK CONNECTION OF CONNECTOR


    1. Turn the engine switch off.

    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

    3. Check that the connector are properly connected to occupant detection ECU.

      Result
      Proceed to
      Connector is properly connected
      Connector is not properly connected

    Connector is not properly connected

    CONNECT CONNECTOR

    Connector is properly connected

  3. CHECK CONNECTOR


    1. Disconnect the connector from the occupant detection ECU.

    2. Check that the connector (on the occupant detection ECU side) are not damaged.

      Result
      Proceed to
      Connectors are not deformed or damaged
      Connectors are deformed or damaged

    Connectors are deformed or damaged

    REPLACE HARNESS OR CONNECTOR

    Connectors are not deformed or damaged

  4. CHECK HARNESS AND CONNECTOR (OCCUPANT DETECTION ECU - BATTERY AND BODY GROUND)


    1. A01HIUHC09
      *a

      Front view of wire harness connector

      (to Occupant Detection ECU)

      Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

    2. Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      f15-1 (+B) - Body ground Always 11 to 14 V
      f15-6 (IG2) - Body ground Engine switch on (IG)

    4. Turn the engine switch off.

    5. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      f15-3 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK DTC


    1. Connect the connector to the occupant detection ECU.

    2. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

    3. Turn the engine switch on (IG), and wait for at least 60 seconds.

    4. Clear the DTCs.

      Click here


      Body Electrical > Occupant Detection > Clear DTCs

      Tech Tips


      • First clear the DTCs stored in the occupant detection ECU, and then clear the DTCs stored in the airbag ECU assembly.

      • Use the GTS to clear the DTCs of the occupant detection ECU, otherwise the DTCs cannot be cleared.

    5. Turn the engine switch off.

    6. Turn the engine switch on (IG), and wait for at least 60 seconds.

    7. Check for DTCs.

      Click here


      Body Electrical > Occupant Detection > Trouble Codes
      Result
      Proceed to
      DTC B1794 is not output
      DTC B1794 is output

      Tech Tips

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


    DTC B1794 is not output

    USE SIMULATION METHOD TO CHECK Click here

    DTC B1794 is output

  6. REPLACE OCCUPANT DETECTION ECU


    1. Turn the engine switch off.

    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

    3. Replace the occupant detection ECU.

      Click here

      Tech Tips

      Perform the inspection using parts from a normal vehicle when possible.

      Result
      Proceed to
      NEXT

    NEXT

  7. PERFORM ZERO POINT CALIBRATION


    1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

    2. Turn the engine switch on (IG).

    3. Perform the zero point calibration.

      Click here

      Result
      Proceed to
      "Zero Point Calibration is complete." is displayed

    "Zero Point Calibration is complete." is displayed

  8. PERFORM SENSITIVITY CHECK


    1. Perform the sensitivity check.

      Click here

      Standard
      27 to 33 kg (59.5 to 72.8 lb)
      Result
      Proceed to
      NEXT

    NEXT

    END (OCCUPANT DETECTION ECU WAS DEFECTIVE)