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
Tip:

  • 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

C256410E18

CAUTION / NOTICE / HINT

Note:

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

    Click hereClick hereClick 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 power switch to on (IG), and wait for at least 60 seconds.

    2. Clear the DTCs.

      Click here

      Body Electrical > Occupant Detection > Clear DTCs

      Tip:

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

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

    3. Turn the power switch off.

    4. Turn the power switch to 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
      Tip:

      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 power switch off.

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

    3. Check that the connector is properly connected to the 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) is 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 - AUXILIARY BATTERY AND BODY GROUND)

    1. C239235C16

      *a

      Front view of wire harness connector

      (to Occupant Detection ECU)

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

    2. Turn the power switch to on (IG).

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      d16-1 (+B) - Body ground

      Always

      11 to 14 V

      d16-6 (IG2) - Body ground

      Power switch on (IG)

    4. Turn the power switch off.

    5. Disconnect the cable from the negative (-) auxiliary 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

      d16-3 (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 (-) auxiliary battery terminal, and wait for at least 2 seconds.

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

    4. Clear the DTCs.

      Click here

      Body Electrical > Occupant Detection > Clear DTCs

      Tip:

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

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

    5. Turn the power switch off.

    6. Turn the power switch to 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
      Tip:

      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 power switch off.

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

    3. Replace the occupant detection ECU.

      Click here

      Tip:

      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 (-) auxiliary battery terminal, and wait for at least 2 seconds.

    2. Turn the power switch to 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)