Dtc B1925/78 Short In Rear Pretensioner Squib Lh Circuit

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

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

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

CHECK FLOOR WIRE NO.2 (REAR PRETENSIONER SQUIB LH CIRCUIT)

CHECK CENTER AIRBAG SENSOR ASSEMBLY

DTC B1925/78 Short in Rear Pretensioner Squib LH Circuit

DTC B1926/78 Open in Rear Pretensioner Squib LH Circuit

DTC B1927/78 Short to GND in Rear Pretensioner Squib LH Circuit

DTC B1928/78 Short to B+ in Rear Pretensioner Squib LH Circuit


DESCRIPTION

The rear pretensioner squib LH circuit consists of the center airbag sensor assembly and the rear 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 rear pretensioner squib LH circuit.

DTC No.
DTC Detection Condition
Trouble Area
B1925/78
  1. The center airbag sensor assembly receives a line short circuit signal 5 times in the rear pretensioner squib LH circuit during primary check.
  2. Rear pretensioner squib LH malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire No.2
  2. Rear seat outer belt assembly LH (Rear pretensioner squib LH)
  3. Center airbag sensor assembly
B1926/78
  1. The center airbag sensor assembly receives an open circuit signal in the rear pretensioner squib LH circuit for 2 seconds.
  2. Rear pretensioner squib LH malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire No.2
  2. Rear seat outer belt assembly LH (Rear pretensioner squib LH)
  3. Center airbag sensor assembly
B1927/78
  1. The center airbag sensor assembly receives a short circuit to ground signal in the rear pretensioner squib LH circuit for 0.5 seconds.
  2. Rear pretensioner squib LH malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire No.2
  2. Rear seat outer belt assembly LH (Rear pretensioner squib LH)
  3. Center airbag sensor assembly
B1928/78
  1. The center airbag sensor assembly receives a short circuit to B+ signal in the rear pretensioner squib LH circuit for 0.5 seconds.
  2. Rear pretensioner squib LH malfunction
  3. Center airbag sensor assembly malfunction
  1. Floor wire No.2
  2. Rear seat outer belt assembly LH (Rear pretensioner squib LH)
  3. Center airbag sensor assembly

WIRING DIAGRAM


Lexus Gs430, Gs300. Uzs190 Grs190.Supplemental Restraint System.Airbag System. Dtc B1925/78 Short In Rear 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 REAR SEAT OUTER BELT ASSEMBLY LH (REAR PRETENSIONER SQUIB LH)


    Lexus Gs430, Gs300. Uzs190 Grs190.Supplemental Restraint System.Airbag System. Dtc B1925/78 Short In Rear 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 connector from the rear 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 rear seat outer belt assembly LH (Rear 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 B1925, B1926, B1927, B1928 or 78 is not output.
    HINT:
    Codes other than DTC B1925, B1926, B1927, B1928 and 78 may be output at this time, but they are not related to this check.


OK
REPLACE REAR SEAT OUTER BELT ASSEMBLY LH
NG


2.CHECK FLOOR WIRE NO.2 (REAR PRETENSIONER SQUIB LH CIRCUIT)


    Lexus Gs430, Gs300. Uzs190 Grs190.Supplemental Restraint System.Airbag System. Dtc B1925/78 Short In Rear 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 SST from connector "C".

  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
      W23-1 (RL+) -
      Body ground
      		Engine switch on (IG)
      		Below 1 V
      W23-2 (RL-) -
      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
      W23-1 (RL+) -
      W23-2 (RL-)
      		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
      W23-1 (RL+) -
      Body ground
      		Always
      		1 MΩ or higher
      W23-2 (RL-)
      Body ground
      		Always
      		1 MΩ or higher

  1. Check the 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
      W23-1 (RL+) -
      W23-2 (RL-)
      		Always
      		1 MΩ or higher


NG
REPAIR OR REPLACE FLOOR WIRE NO.2
OK


3.CHECK CENTER AIRBAG SENSOR ASSEMBLY


    Lexus Gs430, Gs300. Uzs190 Grs190.Supplemental Restraint System.Airbag System. Dtc B1925/78 Short In Rear Pretensioner Squib Lh Circuit

  1. Connect the connectors to the rear 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 B1925, B1926, B1927, B1928 or 78 is not output.
    HINT:
    Codes other than DTC B1925, B1926, B1927, B1928 and 78 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