Dtc B1870/66 Short In Driver Side Front Seat Cushion Squib Circuit

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

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK CONNECTORS

CHECK SRS SEAT CUSHION AIRBAG ASSEMBLY LH (SEAT CUSHION SQUIB)

CHECK FLOOR WIRE (SEAT CUSHION SQUIB LH CIRCUIT)

CHECK DTC

DTC B1870/66 Short in Driver Side Front Seat Cushion Squib Circuit

DTC B1871/66 Open in Driver Side Front Seat Cushion Squib Circuit

DTC B1872/66 Short to GND in Driver Side Front Seat Cushion Squib Circuit

DTC B1873/66 Short to B+ in Driver Side Front Seat Cushion Squib Circuit


DESCRIPTION

The seat cushion squib LH circuit consists of the airbag sensor assembly and SRS seat cushion airbag assembly LH.
The airbag sensor assembly uses this circuit to deploy the airbag when deployment conditions are met.
These DTCs are stored when a malfunction is detected in the seat cushion squib LH circuit.

DTC No.
DTC Detection Condition
Trouble Area
B1870/66
  1. The airbag sensor assembly receives a line short circuit signal in the seat cushion squib LH circuit during primary check.
  2. Seat cushion squib LH malfunction
  3. Airbag sensor assembly malfunction
  1. Floor wire
  2. SRS seat cushion airbag assembly LH (Seat cushion squib LH)
  3. Airbag sensor assembly
B1871/66
  1. The airbag sensor assembly receives an open circuit signal in the seat cushion squib LH circuit.
  2. Seat cushion squib LH malfunction
  3. Airbag sensor assembly malfunction
B1872/66
  1. The airbag sensor assembly receives a short circuit to ground signal in the seat cushion squib LH circuit.
  2. Seat cushion squib LH malfunction
  3. Airbag sensor assembly malfunction
B1873/66
  1. The airbag sensor assembly receives a short circuit to B+ signal in the seat cushion squib LH circuit.
  2. Seat cushion squib LH malfunction
  3. Airbag sensor assembly malfunction

WIRING DIAGRAM


Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1870/66 Short In Driver Side Front Seat Cushion Squib Circuit


INSPECTION PROCEDURE

HINT:
  1. Perform the simulation method by selecting check mode (Signal Check) using the Techstream (YARIS_NCP93 RM000000XFF0ASX.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 RM00000135202EX.html).
1.CHECK CONNECTORS


    Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1870/66 Short In Driver Side Front Seat Cushion Squib Circuit

  1. Turn the ignition switch off.

  1. Disconnect the cable from the negative (-) battery terminal.

    CAUTION:
    Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

  1. Check that the connectors are properly connected to the SRS seat cushion airbag assembly LH and airbag sensor assembly.

    OK:
    The connectors are properly connected.
    HINT:
    If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

  1. Disconnect the connectors from the SRS seat cushion airbag assembly LH and airbag sensor assembly.

  1. Check that the terminals of the connectors are not damaged.

    OK:
    The terminals are not deformed or damaged.

  1. Check that the short spring for the floor wire with the activation prevention mechanism is not deformed or damaged.

    OK:
    The short spring is not deformed or damaged.
    Text in Illustration
    *1
    		SRS Seat Cushion Airbag Assembly LH
    *2
    		Airbag Sensor Assembly
    *3
    		Floor Wire


NG
REPLACE FLOOR WIRE
OK


2.CHECK SRS SEAT CUSHION AIRBAG ASSEMBLY LH (SEAT CUSHION SQUIB)
SST
09843-18061


    Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1870/66 Short In Driver Side Front Seat Cushion Squib Circuit

  1. Connect the connector to the airbag sensor assembly.

  1. Connect SST (resistance 2.1 Ω) to connector C.

    CAUTION:
    Never connect the tester to the SRS seat cushion airbag assembly LH (seat cushion squib LH) for measurement, as this may lead to a serious injury due to airbag deployment.
    NOTICE:
    1. Do not forcibly insert SST into the terminals of the connector when connecting.
    2. Insert SST straight into the terminals of the connector.
SST
09843-18061

  1. Connect the cable to the negative (-) battery terminal.

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

  1. Clear the DTCs stored in memory (YARIS_NCP93 RM000000XFE0EEX.html).

  1. Turn the ignition switch off.

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

  1. Check for DTCs (YARIS_NCP93 RM000000XFE0EEX.html).

    OK:
    DTC B1870/66, B1871/66, B1872/66 or B1873/66 is not output.
    HINT:
    Codes other than DTCs B1870/66, B1871/66, B1872/66 and B1873/66 may be output at this time, but they are not related to this check.
    Text in Illustration
    *1
    		SRS Seat Cushion Airbag Assembly LH
    *2
    		Airbag Sensor Assembly
    *3
    		Connector C
    *a
    		Front view of wire harness connector
    (to SRS Seat Cushion Airbag Assembly LH)

  1. Turn the ignition switch off.

  1. Disconnect the cable from the negative (-) battery terminal.

    CAUTION:
    Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

  1. Disconnect SST from connector C.



NG
Go to step 3
OK

REPLACE SRS SEAT CUSHION AIRBAG ASSEMBLY LH (YARIS_NCP93 RM000001WB001IX.html)

3.CHECK FLOOR WIRE (SEAT CUSHION SQUIB LH CIRCUIT)


    Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1870/66 Short In Driver Side Front Seat Cushion Squib Circuit

  1. Disconnect the floor wire from the airbag sensor assembly.

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

    1. Connect the cable to the negative (-) battery terminal.

    2. Turn the ignition switch to ON.

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

      Standard Voltage:
      Tester Connection
      		Switch Condition
      		Specified Condition
      J88-1 (FCD-) - Body ground
      		Ignition switch ON
      		Below 1 V
      J88-2 (FCD+) - Body ground
      		Ignition switch ON
      		Below 1 V

  1. Check for an open in the circuit.

    1. Turn the ignition switch off.

    2. Disconnect the cable from the negative (-) battery terminal.

      CAUTION:
      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

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

      Standard Resistance:
      Tester Connection
      		Condition
      		Specified Condition
      J88-1 (FCD-) - J88-2 (FCD+)
      		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
      J88-1 (FCD-) - Body ground
      		Always
      		1 MΩ or higher
      J88-2 (FCD+) - 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 (YARIS_NCP93 RM000000XFD0E4X.html).

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

      Standard Resistance:
      Tester Connection
      		Condition
      		Specified Condition
      J88-1 (FCD-) - J88-2 (FCD+)
      		Always
      		1 MΩ or higher
      Text in Illustration
      *1
      		SRS Seat Cushion Airbag Assembly LH
      *2
      		Airbag Sensor Assembly
      *3
      		Floor Wire
      *4
      		Connector C
      *a
      		Front view of wire harness connector
      (to SRS Seat Cushion Airbag Assembly LH)

  1. Restore the released activation prevention mechanism of connector B to the original condition.



NG
REPLACE FLOOR WIRE
OK


4.CHECK DTC


    Yaris. Ncp93, 131.Supplemental Restraint Systems.Airbag System (For Sedan). Dtc B1870/66 Short In Driver Side Front Seat Cushion Squib Circuit

  1. Connect the connectors to the SRS seat cushion airbag assembly LH and airbag sensor assembly.

  1. Connect the cable to the negative (-) battery terminal.

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

  1. Clear the DTCs stored in memory (YARIS_NCP93 RM000000XFE0EEX.html).

  1. Turn the ignition switch off.

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

  1. Check for DTCs (YARIS_NCP93 RM000000XFE0EEX.html).

    OK:
    DTC B1870/66, B1871/66, B1872/66 or B1873/66 is not output.
    Text in Illustration
    *1
    		SRS Seat Cushion Airbag Assembly LH
    *2
    		Airbag Sensor Assembly
    HINT:
    Codes other than DTCs B1870/66, B1871/66, B1872/66 and B1873/66 may be output at this time, but they are not related to this check.


NG
REPLACE AIRBAG SENSOR ASSEMBLY (YARIS_NCP93 RM000000V6U02AX.html)
OK

USE SIMULATION METHOD TO CHECK (YARIS_NCP93 RM00000135202EX.html)