Dtc B1860/64 Short In Driver Side Knee Airbag Squib Circuit

Restraints. Lexus Is250, Is220D. Gse20 Ale20
Supplemental Restraint System. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK DRIVER SIDE KNEE AIRBAG ASSEMBLY (DRIVER SIDE KNEE AIRBAG SQUIB)

CHECK CONNECTOR

CHECK INSTRUMENT PANEL WIRE (DRIVER SIDE KNEE AIRBAG SQUIB CIRCUIT)

CHECK CENTER AIRBAG SENSOR ASSEMBLY

DTC B1860/64 Short in Driver Side Knee Airbag Squib Circuit

DTC B1861/64 Open in Driver Side Knee Airbag Squib Circuit

DTC B1862/64 Short to GND in Driver Side Knee Airbag Squib Circuit

DTC B1863/64 Short to B+ in Driver Side Knee Airbag Squib Circuit


DESCRIPTION

The driver side knee airbag squib circuit consists of the center airbag sensor assembly and the driver side knee airbag assembly.
This circuit instructs the SRS to deploy when deployment conditions are met.
These DTCs are recorded when a malfunction is detected in the driver side knee airbag squib circuit.

DTC No.
DTC Detecting Condition
Trouble Area
B1860/64
  1. The center airbag sensor assembly receives a line short circuit signal 5 times in the driver side knee airbag squib circuit during primary check.
  2. Driver side knee airbag squib malfunction
  3. Center airbag sensor assembly malfunction
  1. Instrument panel wire
  2. Driver side knee airbag assembly (Driver side knee airbag squib)
  3. Center airbag sensor assembly
B1861/64
  1. The center airbag sensor assembly receives an open circuit signal in the driver side knee airbag squib circuit for 2 seconds.
  2. Driver side knee airbag squib malfunction
  3. Center airbag sensor assembly malfunction
  1. Instrument panel wire
  2. Driver side knee airbag assembly (Driver side knee airbag squib)
  3. Center airbag sensor assembly
B1862/64
  1. The airbag sensor assembly center receives a short circuit to ground signal in the driver side knee airbag squib circuit for 0.5 seconds.
  2. Driver side knee airbag squib malfunction
  3. Center airbag sensor assembly malfunction
  1. Instrument panel wire
  2. Driver side knee airbag assembly (Driver side knee airbag squib)
  3. Center airbag sensor assembly
B1863/64
  1. The airbag sensor assembly center receives a short circuit to B+ signal in the driver side knee airbag squib circuit for 0.5 seconds.
  2. Driver side knee airbag squib malfunction
  3. Center airbag sensor assembly malfunction
  1. Instrument panel wire
  2. Driver side knee airbag assembly (Driver side knee airbag squib)
  3. Center airbag sensor assembly

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System. Dtc B1860/64 Short In Driver Side Knee Airbag Squib 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 DRIVER SIDE KNEE AIRBAG ASSEMBLY (DRIVER SIDE KNEE AIRBAG SQUIB)


    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System. Dtc B1860/64 Short In Driver Side Knee Airbag Squib 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 driver side knee airbag assembly.

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

    CAUTION:
    Never connect a tester to the driver side knee airbag assembly (driver side knee airbag 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 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 the 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 for DTCs (Click here).

    OK:
    DTC B1860, B1861, B1862, B1863 or 64 is not output.
    HINT:
    Codes other than DTC B1860, B1861, B1862, B1863 and 64 may be output at this time, but they are not related to this check.


OK
REPLACE DRIVER SIDE KNEE AIRBAG ASSEMBLY
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 instrument panel wire connector (on the driver side knee airbag assembly 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 INSTRUMENT PANEL WIRE
OK


3.CHECK INSTRUMENT PANEL WIRE (DRIVER SIDE KNEE AIRBAG SQUIB CIRCUIT)


    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System. Dtc B1860/64 Short In Driver Side Knee Airbag Squib Circuit

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

  1. Check for a 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.

      Standard voltage:
      Tester connection
      		Condition
      		Specified condition
      J20-1 (DK+) - Body ground
      		Engine switch on (IG)
      		Below 1 V
      J20-2 (DK-) - Body ground
      		Engine switch on (IG)
      		Below 1 V

  1. Check for an 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.

      Standard resistance:
      Tester connection
      		Condition
      		Specified condition
      J20-1 (DK+) - J20-2 (DK-)
      		Always
      		Below 1 Ω

  1. Check for a short to ground in the circuit.

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

      Standard resistance:
      Tester connection
      		Condition
      		Specified condition
      J20-1 (DK+) - Body ground
      		Always
      		1 MΩ or higher
      J20-2 (DK-) - Body ground
      		Always
      		1 MΩ or higher

  1. Check for a 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.

      Standard resistance:
      Tester connection
      		Condition
      		Specified condition
      J20-1 (DK+) - J20-2 (DK-)
      		Always
      		1 MΩ or higher


NG
REPAIR OR REPLACE INSTRUMENT PANEL WIRE
OK


4.CHECK CENTER AIRBAG SENSOR ASSEMBLY


    Lexus Is250, Is220D. Gse20 Ale20.Supplemental Restraint System.Airbag System. Dtc B1860/64 Short In Driver Side Knee Airbag Squib Circuit

  1. Connect the connectors to the driver side knee airbag assembly 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 stored DTCs in the 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 for DTCs (Click here).

    OK:
    DTC B1860, B1861, B1862, B1863 or 64 is not output.
    HINT:
    Codes other than DTC B1860, B1861, B1862, B1863 and 64 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