Dtc B1794 Open In Occupant Classification Ecu Battery Positive Line

Vehicle Interior. Yaris. Ncp93, 131
Supplemental Restraint Systems. Yaris. Ncp93, 131

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK BATTERY

CHECK HARNESS AND CONNECTOR (SOURCE VOLTAGE)

CHECK FRONT SEAT WIRE RH (SOURCE VOLTAGE)

CHECK FOR DTC

REPLACE OCCUPANT CLASSIFICATION ECU

PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK

DTC B1794 Open in Occupant Classification ECU Battery Positive Line


DESCRIPTION

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

DTC Code
DTC Detection Condition
Trouble Area
B1794
One of following conditions is met:
  1. Occupant classification ECU circuit malfunction
  2. Occupant classification ECU malfunction
  1. ECU-B No. 2 fuse
  2. IG2 fuse
  3. Front seat wire RH
  4. Harness or connector
  5. Occupant classification ECU
HINT:
  1. When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1794 of the occupant classification system.
  2. Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.

WIRING DIAGRAM


Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1794 Open In Occupant Classification Ecu Battery Positive Line


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
1.CHECK BATTERY

  1. Measure the voltage of the battery.

    Standard voltage:
    11 to 14 V


NG
REPLACE BATTERY
OK


2.CHECK HARNESS AND CONNECTOR (SOURCE VOLTAGE)


    Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1794 Open In Occupant Classification Ecu Battery Positive Line

  1. Turn the ignition switch off.

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

  1. Disconnect the front seat wire RH connector from the floor wire.

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

  1. Turn the ignition switch to ON.

  1. Measure the resistance and voltage according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    JX1-3 - Body ground
    		Always
    		Below 1 Ω
    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    JX1-6 - Body ground
    		Always
    		11 to 14 V
    JX1-7 - Body ground
    		Ignition switch ON
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Front Seat Wire RH)


NG
REPLACE HARNESS OR CONNECTOR
OK


3.CHECK FRONT SEAT WIRE RH (SOURCE VOLTAGE)


    Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1794 Open In Occupant Classification Ecu Battery Positive Line

  1. Turn the ignition switch off.

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

  1. Connect the front seat wire RH connector to the floor wire.

  1. Disconnect the occupant classification ECU connector.

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

  1. Turn the ignition switch to ON.

  1. Measure the resistance and voltage according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    X4-3 - Body ground
    		Always
    		Below 1 Ω
    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    X4-1 - Body ground
    		Always
    		11 to 14 V
    X4-6 - Body ground
    		Ignition switch ON
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Occupant Classification ECU)


NG
REPLACE FRONT SEAT WIRE RH (YARIS_NCP93 RM000001WB001FX.html)
OK


4.CHECK FOR DTC

  1. Turn the ignition switch off.

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

  1. Connect the connectors to the occupant classification ECU.

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

  1. Turn the ignition switch to ON, and wait for at least 60 seconds.

  1. Clear any DTCs stored in the memory (YARIS_NCP93 RM0000010VK072X.html).

    HINT:
    1. First clear DTCs stored in the occupant classification ECU and then in the airbag sensor assembly.
    2. Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.

  1. Turn the ignition switch off.

  1. Turn the ignition switch to ON, and wait for at least 60 seconds.

  1. Using the Techstream, check for DTCs of the occupant classification ECU (YARIS_NCP93 RM0000010VK072X.html).

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


NG
Go to step 5
OK

USE SIMULATION METHOD TO CHECK (YARIS_NCP93 RM0000010VJ076X.html)

5.REPLACE OCCUPANT CLASSIFICATION ECU

  1. Turn the ignition switch off.

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

  1. Replace the occupant classification ECU (YARIS_NCP93 RM0000011JG02SX.html).

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

NEXT


6.PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK

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

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Using the Techstream, perform Zero Point Calibration and Sensitivity Check (YARIS_NCP93 RM0000010VN073X.html).


NEXT

END