Dtc B1905/74 Short In Front Pretensioner Squib Lh Circuit

Restraints. Lexus Gs430, Gs300. Uzs190 Grs190
Supplemental Restraint System. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

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

CHECK CONNECTOR

CHECK FLOOR WIRE NO.2 (FRONT PRETENSION SQUIB LH CIRCUIT)

CHECK CENTER AIRBAG SENSOR ASSEMBLY

DTC B1905/74 Short in Front Pretensioner Squib LH Circuit

DTC B1906/74 Open in Front Pretensioner Squib LH Circuit

DTC B1907/74 Short to GND in Front Pretensioner Squib LH Circuit

DTC B1908/74 Short to B+ in Front Pretensioner Squib LH Circuit


DESCRIPTION

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

DTC No.
DTC Detection Condition
Trouble Area
B1905/74
  1. The center airbag sensor assembly receives a line short circuit signal 5 times in the front pretensioner squib LH circuit during primary check.
  2. Front pretensioner squib LH malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire No.2
  2. Front seat outer belt assembly LH (Front pretensioner squib LH)
  3. Center airbag sensor assembly
B1906/74
  1. The center airbag sensor assembly receives an open circuit signal in the front pretensioner squib LH circuit for 2 seconds.
  2. Front pretensioner squib LH malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire No.2
  2. Front seat outer belt assembly LH (Front pretensioner squib LH)
  3. Center airbag sensor assembly
B1907/74
  1. The center airbag sensor assembly receives a short circuit to ground signal in the front pretensioner squib LH circuit for 0.5 seconds.
  2. Front pretensioner squib LH malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire No.2
  2. Front seat outer belt assembly LH (Front pretensioner squib LH)
  3. Center airbag sensor assembly
B1908/74
  1. The center airbag sensor assembly receives a short circuit to B+ signal in the front pretensioner squib LH circuit for 0.5 seconds.
  2. Front pretensioner squib LH malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire No.2
  2. Front seat outer belt assembly LH (Front pretensioner squib LH)
  3. Center airbag sensor assembly

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Supplemental Restraint System.Airbag System. Dtc B1905/74 Short In Front Pretensioner Squib Lh Circuit


INSPECTION PROCEDURE

HINT:
  1. Perform the simulation method by selecting the "check mode" (signal check) with the intelligent tester (Click here).
  2. After selecting the "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 (Click here).
1.CHECK FRONT SEAT OUTER BELT ASSEMBLY LH (FRONT PRETENSIONER SQUIB LH)


    Lexus Gs430, Gs300. Uzs190 Grs190.Supplemental Restraint System.Airbag System. Dtc B1905/74 Short In Front Pretensioner Squib Lh Circuit

  1. Turn the engine 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 (Front pretensioner squib LH) for measurement, as the 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 straight the SST into the terminals of the connector.
SST
09843-18060

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

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

  1. Clear the DTCs stored in memory (Click here).

  1. Turn the engine switch off.

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

  1. Check the DTCs (Click here).

    OK:
    DTC B1905, B1906, B1907, B1908 or 74 is not output.
    HINT:
    Codes other than DTC B1905, B1906, B1907, B1908 and 74 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 engine 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 No.2 connector (on the front seat outer belt assembly LH side) is not damaged.

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


NG
REPAIR OR REPLACE FLOOR WIRE NO.2
OK


3.CHECK FLOOR WIRE NO.2 (FRONT PRETENSION SQUIB LH CIRCUIT)


    Lexus Gs430, Gs300. Uzs190 Grs190.Supplemental Restraint System.Airbag System. Dtc B1905/74 Short In Front Pretensioner Squib Lh Circuit

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

  1. Check the 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 engine switch on (IG).

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

      Voltage:
      Tester connection
      		Condition
      		Specified condition
      W9-1 (L+) -
      Body ground
      		Engine switch on (IG)
      		Below 1 V
      W9-2 (L-) -
      Body ground
      		Engine switch on (IG)
      		Below 1 V

  1. Check the open in the circuit.

    1. Turn the engine switch off.

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

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

      Resistance:
      Tester connection
      		Condition
      		Specified condition
      W9-1 (L+) -
      W9-2 (L-)
      		Always
      		Below 1 Ω

  1. Check the short to ground in the circuit.

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

      Resistance:
      Tester connection
      		Condition
      		Specified condition
      W9-1 (L+) -
      Body ground
      		Always
      		1 MΩ or higher
      W9-2 (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" (Click here).

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

      Resistance:
      Tester connection
      		Condition
      		Specified condition
      W9-1 (L+) -
      W9-2 (L-)
      		Always
      		1 MΩ or higher


NG
REPAIR OR REPLACE FLOOR WIRE NO.2
OK


4.CHECK CENTER AIRBAG SENSOR ASSEMBLY


    Lexus Gs430, Gs300. Uzs190 Grs190.Supplemental Restraint System.Airbag System. Dtc B1905/74 Short In Front Pretensioner Squib Lh 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 engine switch on (IG), and wait for at least 60 seconds.

  1. Clear the DTCs stored in memory (Click here).

  1. Turn the engine switch off.

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

  1. Check the DTCs (Click here).

    OK:
    DTC B1905, B1906, B1907, B1908 or 74 is not output.
    HINT:
    Codes other than DTC B1905, B1906, B1907, B1908 and 74 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