OCCUPANT CLASSIFICATION SYSTEM, Diagnostic DTC:B1793

DTC Code DTC Name
B1793 Occupant Classification Sensor Power Supply Circuit Malfunction

DESCRIPTION

The occupant classification sensor power supply circuit consists of the occupant detection ECU, front and rear occupant classification sensor LH.

DTC B1793 is stored when a malfunction is detected in the occupant classification sensor power supply circuit.

DTC No. Detection Item DTC Detection Condition Trouble Area
B1793 Occupant Classification Sensor Power Supply Circuit Malfunction

    One of the following conditions is met:

  • Occupant detection ECU detects a line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to +B signal in the occupant classification sensor power supply circuit for 2 seconds.

  • Open circuit in the occupant classification sensor wire harness.

  • Occupant detection ECU malfunction.

  • Front seat adjuster assembly RH (Front and rear occupant classification sensor LH)

  • Front seat wire RH

  • Occupant detection ECU

Tech Tips


  • When DTC B1650/32 is stored as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1793 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

A01HDXOE01

CAUTION / NOTICE / HINT

Note

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

Click here

Tech Tips


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

  • In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may cause problems, such as seat rail deformation. Hold the seat up only for as long as necessary.

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 B1793 is not output
      DTC B1793 is output

      Tech Tips

      DTCs other than DTC B1793 may be output at this time, but they are not related to this check.


    DTC B1793 is not output

    USE SIMULATION METHOD TO CHECK Click here

    DTC B1793 is output

  2. CHECK CONNECTION OF CONNECTORS


    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 connectors are properly connected to the occupant detection ECU, front and rear occupant classification sensor LH.

      Result
      Proceed to
      Connectors are properly connected
      Connectors are not properly connected

    Connectors are not properly connected

    CONNECT CONNECTORS

    Connectors are properly connected

  3. CHECK CONNECTORS


    1. A01HI1LC05
      *1 Front Occupant Classification Sensor LH
      *2 Rear Occupant Classification Sensor LH
      *3 Occupant Detection ECU
      *4 Front Seat Wire RH

      Disconnect the connectors from the occupant detection ECU, front and rear occupant classification sensor LH.

    2. Check that the connectors (on the occupant detection ECU side, front and rear occupant classification sensor LH side) are not damaged.

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

    Connectors are deformed or damaged

    REPLACE FRONT SEAT WIRE RH

    Connectors are not deformed or damaged

  4. CHECK FRONT SEAT WIRE RH


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

      A01HHMVC05
      *1 Front Seat Wire RH *2 Front Occupant Classification Sensor LH
      *3 Rear Occupant Classification Sensor LH *4 Occupant Detection ECU
      *5 Connector B *6 Connector C
      *7 Connector E - -
      *a

      Front view of wire harness connector

      (to Occupant Detection ECU)

      		 *b

      Front view of wire harness connector

      (to Front Occupant Classification Sensor LH)
      *c

      Front view of wire harness connector

      (to Rear Occupant Classification Sensor LH)

      		 - -

    2. Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      f14-1 (SVC1) - Body ground Engine switch on (IG) Below 1 V
      f14-2 (SVC3) - Body ground

    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
      f14-1 (SVC1) - f17-1 (SVC) Always Below 1 Ω
      f14-2 (SVC3) - f18-1 (SVC)
      f14-1 (SVC1) - f14-2 (SVC3) 1 MΩ or higher
      f14-1 (SVC1) - Body ground
      f14-2 (SVC3) - Body ground
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FRONT SEAT WIRE RH

    OK

  5. CHECK DTC


    1. Connect the connectors to occupant detection ECU, front and rear occupant classification sensor LH.

    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 B1793 is not output
      DTC B1793 is output

      Tech Tips

      DTCs other than DTC B1793 may be output at this time, but they are not related to this check.


    DTC B1793 is not output

    USE SIMULATION METHOD TO CHECK Click here

    DTC B1793 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 not displayed

    "Zero Point Calibration is complete." is not displayed

    REPLACE FRONT SEAT ADJUSTER ASSEMBLY RH (FRONT AND REAR OCCUPANT CLASSIFICATION SENSOR LH) Click here

    "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
      OK
      NG

    NG

    GO TO STEP 10 Click here

    OK

  9. CHECK DTC


    1. 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.

    2. Turn the engine switch off.

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

    4. Check for DTCs.

      Click here


      Body Electrical > Occupant Detection > Trouble Codes
      Result
      Proceed to
      DTC B1793 is not output
      DTC B1793 is output

      Tech Tips

      DTCs other than DTC B1793 may be output at this time, but they are not related to this check.


    DTC B1793 is not output

    END (OCCUPANT DETECTION ECU WAS DEFECTIVE)

    DTC B1793 is output

  10. REPLACE FRONT SEAT ADJUSTER ASSEMBLY RH (FRONT AND REAR OCCUPANT CLASSIFICATION SENSOR LH)


    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 front seat adjuster assembly RH.

      Click here

      Tech Tips

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

      Result
      Proceed to
      NEXT

    NEXT

  11. 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

  12. 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 (FRONT SEAT ADJUSTER ASSEMBLY RH [FRONT AND REAR OCCUPANT CLASSIFICATION SENSOR LH] WAS DEFECTIVE)