Dtc B1900/73 Short In Front Driver Side Pretensioner Squib Circuit

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

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK FRONT SEAT OUTER BELT ASSEMBLY LH (DRIVER SIDE FRONT PRETENSIONER SQUIB)

CHECK CONNECTOR

CHECK FLOOR WIRE (DRIVER SIDE FRONT PRETENSIONER SQUIB CIRCUIT)

CHECK CENTER AIRBAG SENSOR ASSEMBLY

DTC B1900/73 Short in Front Driver Side Pretensioner Squib Circuit

DTC B1901/73 Open in Front Driver Side Pretensioner Squib Circuit

DTC B1902/73 Short to GND in Front Driver Side Pretensioner Squib Circuit

DTC B1903/73 Short to B+ in Front Driver Side Pretensioner Squib Circuit


DESCRIPTION

The driver side front pretensioner squib circuit consists of the center airbag sensor assembly and the front seat outer belt assembly LH.
This circuit signals the SRS to deploy when deployment conditions are met.
These DTCs are recorded when a malfunction is detected in the driver side front pretensioner squib circuit.

DTC No.
DTC Detection Condition
Trouble Area
B1900/73
  1. Center airbag sensor assembly detects line short circuit signal in driver side front pretensioner squib circuit 5 times during primary check.
  2. Driver side front pretensioner squib malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire
  2. Front seat outer belt assembly LH (Driver side front pretensioner squib)
  3. Center airbag sensor assembly
B1901/73
  1. Center airbag sensor assembly detects open circuit signal in driver side front pretensioner squib circuit for 2 seconds.
  2. Driver side front pretensioner squib malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire
  2. Front seat outer belt assembly LH (Driver side front pretensioner squib)
  3. Center airbag sensor assembly
B1902/73
  1. Center airbag sensor assembly detects short circuit to ground signal in driver side front pretensioner squib circuit for 0.5 seconds.
  2. Driver side front pretensioner squib malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire
  2. Front seat outer belt assembly LH (Driver side front pretensioner squib)
  3. Center airbag sensor assembly
B1903/73
  1. Center airbag sensor assembly detects short circuit to B+ signal in driver side front pretensioner squib circuit for 0.5 seconds.
  2. Driver side front pretensioner squib malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire
  2. Front seat outer belt assembly LH (Driver side front pretensioner squib)
  3. Center airbag sensor assembly

WIRING DIAGRAM


Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1900/73 Short In Front Driver Side Pretensioner Squib Circuit


INSPECTION PROCEDURE

HINT:
  1. Perform the simulation method by selecting CHECK MODE (signal check) with the Techstream (YARIS_NCP93 RM000000XFF09MX.html).
  2. After selecting CHECK MODE (signal check), perform the simulation method by wiggling each connector of the airbag system or driving the vehicle on a city or rough road (YARIS_NCP93 RM000000XFD0CVX.html).
1.CHECK FRONT SEAT OUTER BELT ASSEMBLY LH (DRIVER SIDE FRONT PRETENSIONER SQUIB)
Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1900/73 Short In Front Driver Side Pretensioner Squib Circuit
SST
09843-18060

  1. Turn the ignition switch off.

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

  1. Disconnect the connectors from the front seat outer belt assembly LH.

  1. Connect the white wire side of SST (resistance 2.1 Ω) to connector C.

    CAUTION:
    Never connect a tester to the front seat outer belt assembly LH (driver side front pretensioner squib) for measurement, as this may lead to a serious injury due to airbag deployment.
    NOTICE:
    1. Do not forcibly insert the SST into the terminals of the connector when connecting.
    2. Insert the SST straight into the terminals of the connector.

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

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

  1. Clear the DTCs stored in the memory (YARIS_NCP93 RM000000XFE0D2X.html).

  1. Turn the ignition switch off.

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

  1. Check the DTCs (YARIS_NCP93 RM000000XFE0D2X.html).

    OK:
    DTC B1900, B1901, B1902, B1903 and 73 are not output.
    HINT:
    DTCs other than DTC B1900, B1901, B1902, B1903 and 73 may be output at this time, but they are not related to this check.


OK
REPLACE FRONT SEAT OUTER BELT ASSEMBLY LH
NG


2.CHECK CONNECTOR

  1. Turn the ignition switch off.

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

  1. Disconnect the SST from connector C.

  1. Check that the floor wire connector (on the front seat outer belt assembly LH side) is not damaged.

    OK:
    The lock button is not disengaged, and the claw of the lock is not deformed or damaged.


NG
REPAIR OR REPLACE FLOOR WIRE
OK


3.CHECK FLOOR WIRE (DRIVER SIDE FRONT PRETENSIONER SQUIB CIRCUIT)
Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1900/73 Short In Front Driver Side Pretensioner Squib Circuit

  1. Disconnect the connectors from the center airbag sensor assembly.

  1. Check for short to B+ in the circuit.

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

    2. Turn the ignition switch on.

    3. Measure the voltage.

      Standard voltage:
      Tester Connection
      		Switch Condition
      		Specified Condition
      J21-1 (L-) - Body ground
      		Ignition switch ON
      		Below 1 V
      J21-2 (L+) - Body ground
      		Ignition switch ON
      		Below 1 V

  1. Check for open in the circuit.

    1. Turn the ignition switch off.

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

    3. Measure the resistance.

      Standard resistance:
      Tester Connection
      		Condition
      		Specified Condition
      J21-1 (L-) - J21-2 (L+)
      		Always
      		Below 1 Ω

  1. Check for short to ground in the circuit.

    1. Measure the resistance.

      Standard resistance:
      Tester Connection
      		Condition
      		Specified Condition
      J21-1 (L-) - Body ground
      		Always
      		1 MΩ or higher
      J21-2 (L+) - Body ground
      		Always
      		1 MΩ or higher

  1. Check for short in the circuit.

    1. Release the activation prevention mechanism built into connector B (YARIS_NCP93 RM000000XFD0CVX.html).

    2. Measure the resistance.

      Standard resistance:
      Tester Connection
      		Condition
      		Specified Condition
      J21-1 (L-) - J21-2 (L+)
      		Always
      		1 MΩ or higher


NG
REPAIR OR REPLACE FLOOR WIRE
OK


4.CHECK CENTER AIRBAG SENSOR ASSEMBLY
Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1900/73 Short In Front Driver Side Pretensioner Squib Circuit

  1. Connect the connectors to the front seat outer belt assembly LH and the center airbag sensor assembly.

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

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

  1. Clear the DTCs stored in the memory (YARIS_NCP93 RM000000XFE0D2X.html).

  1. Turn the ignition switch off.

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

  1. Check the DTCs (YARIS_NCP93 RM000000XFE0D2X.html).

    OK:
    DTC B1900, B1901, B1902, B1903 and 73 are not output.
    HINT:
    DTCs other than DTC B1900, B1901, B1902, B1903 and 73 may be output at this time, but they are not related to this check.


NG
REPLACE CENTER AIRBAG SENSOR ASSEMBLY
OK

USE SIMULATION METHOD TO CHECK