AIRBAG SYSTEM, Diagnostic DTC:B161C/9A, B161D/9A

DTC Code DTC Name
B161C/9A Lost Communication with Front Satellite Sensor Bus Center
B161D/9A Front Satellite Sensor Bus Center Initialization Incomplete

DESCRIPTION

The front airbag sensor circuit consists of the airbag sensor assembly and front airbag sensor.

The front airbag sensor detects impacts to the vehicle and sends signals to the airbag sensor assembly to determine if the airbag should be deployed.

These DTCs are stored when a malfunction is detected in the front airbag sensor circuit.

DTC No. DTC Detection Condition Trouble Area

B161C/9A

B161D/9A

  • The airbag sensor assembly receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the front airbag sensor circuit.

  • Front airbag sensor malfunction

  • Airbag sensor assembly malfunction

  • Instrument panel wire

  • Engine room main wire

  • Front airbag sensor

  • Airbag sensor assembly

WIRING DIAGRAM

A01UYILE37
*a Front Airbag Sensor
*b Airbag Sensor Assembly

PROCEDURE


  1. CHECK CONNECTORS


    1. Turn the ignition switch off.

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

      CAUTION:

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

    3. Check that the connectors are properly connected to the airbag sensor assembly and front airbag sensor. Also check that the connectors that link the engine room main wire and instrument panel wire are properly connected.

      OK
      The connectors are properly connected.

      Tech Tips

      If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

    4. Disconnect the connectors from the airbag sensor assembly and front airbag sensor. Also disconnect the connectors that link the engine room main wire and instrument panel wire.

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

      OK
      The terminals are not deformed or damaged.

    NG

    REPLACE WIRE HARNESS

    OK

  2. CHECK FRONT AIRBAG SENSOR CIRCUIT (OPEN)


    1. Connect the connectors that link the engine room main wire and instrument panel wire.

      A01UZ9PE01
      Text in Illustration
      *1 Front Airbag Sensor *2 Airbag Sensor Assembly
      *3 Connector B *4 Connector E
      *5 Service Wire - -
      *a

      Front view of wire harness connector

      (to Airbag Sensor Assembly)

      		 *b

      Front view of wire harness connector

      (to Front Airbag Sensor)

    2. Using a service wire, connect terminals 30 (+SL) and 28 (-SL) of connector B.

      Note

      Do not forcibly insert the service wire into the terminals of the connector when connecting.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A15-2 (+SL) - A15-1 (-SL) Always Below 1 Ω

    NG

    CHECK INSTRUMENT PANEL WIRE (OPEN) Click here

    OK

  3. CHECK FRONT AIRBAG SENSOR CIRCUIT (SHORT)


    1. A01V0V8E01
      Text in Illustration
      *1 Front Airbag Sensor
      *2 Airbag Sensor Assembly
      *3 Connector E
      *a

      Front view of wire harness connector

      (to Front Airbag Sensor)

      Disconnect the service wire from connector B.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A15-2 (+SL) - A15-1 (-SL) Always 1 MΩ or higher

    NG

    CHECK INSTRUMENT PANEL WIRE (SHORT) Click here

    OK

  4. CHECK FRONT AIRBAG SENSOR CIRCUIT (SHORT TO B+)


    1. A01V0V8E01
      Text in Illustration
      *1 Front Airbag Sensor
      *2 Airbag Sensor Assembly
      *3 Connector E
      *a

      Front view of wire harness connector

      (to Front Airbag Sensor)

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

    2. Turn the ignition switch to ON (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A15-2 (+SL) - Body ground Ignition switch ON (IG) Below 1 V
      A15-1 (-SL) - Body ground Ignition switch ON (IG) Below 1 V

    4. Turn the ignition switch off.

    5. Disconnect the cable from the negative (-) auxiliary battery terminal.

      CAUTION:

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


    NG

    CHECK INSTRUMENT PANEL WIRE (SHORT TO B+) Click here

    OK

  5. CHECK FRONT AIRBAG SENSOR CIRCUIT (SHORT TO GROUND)


    1. A01V0V8E01
      Text in Illustration
      *1 Front Airbag Sensor
      *2 Airbag Sensor Assembly
      *3 Connector E
      *a

      Front view of wire harness connector

      (to Front Airbag Sensor)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A15-2 (+SL) - Body ground Always 1 MΩ or higher
      A15-1 (-SL) - Body ground Always 1 MΩ or higher

    NG

    CHECK INSTRUMENT PANEL WIRE (SHORT TO GROUND) Click here

    OK

  6. CHECK FRONT AIRBAG SENSOR


    1. Connect the connector to the airbag sensor assembly.

    2. Temporarily replace the front airbag sensor with a new one.

    3. Connect the cable to the negative (-) auxiliary battery terminal.

    4. Turn the ignition switch to ON (IG), and wait for at least 60 seconds.

    5. Clear the DTCs stored in the memory Click here.

    6. Turn the ignition switch off.

    7. Turn the ignition switch to ON (IG), and wait for at least 60 seconds.

    8. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC B161C/9A or B161D/9A is not output. A
      DTC B161C/9A or B161D/9A is output. B

      Tech Tips

      Codes other than DTCs B161C/9A and B161D/9A may be output at this time, but they are not related to this check.

    9. Reinstall the former front airbag sensor, and connect the connector.


    A

    END (FRONT AIRBAG SENSOR WAS DEFECTIVE)

    B

    REPLACE AIRBAG SENSOR ASSEMBLY Click here

  7. CHECK INSTRUMENT PANEL WIRE (OPEN)


    1. Disconnect the instrument panel wire connector from the engine room main wire.

      A01UZKGE01
      Text in Illustration
      *1 Front Airbag Sensor *2 Airbag Sensor Assembly
      *3 Engine Room Main Wire *4 Instrument Panel Wire
      *5 Connector B *6 Connector C
      *7 Service Wire - -
      *a

      Front view of wire harness connector

      (to Airbag Sensor Assembly)

      		 *b

      Front view of wire harness connector

      (to Engine Room Main Wire)

      Tech Tips

      The service wire has already been inserted into connector B.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      AF1-1 (+SL) - AF1-2 (-SL) Always Below 1 Ω

    3. Disconnect the service wire from connector B.


    OK

    REPLACE ENGINE ROOM MAIN WIRE

    NG

    REPLACE INSTRUMENT PANEL WIRE

  8. CHECK INSTRUMENT PANEL WIRE (SHORT)


    1. A01UZW3E01
      Text in Illustration
      *1 Front Airbag Sensor
      *2 Airbag Sensor Assembly
      *3 Engine Room Main Wire
      *4 Instrument Panel Wire
      *5 Connector C
      *a

      Front view of wire harness connector

      (to Engine Room Main Wire)

      Disconnect the instrument panel wire connector from the engine room main wire.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      AF1-1 (+SL) - AF1-2 (-SL) Always 1 MΩ or higher

    OK

    REPLACE ENGINE ROOM MAIN WIRE

    NG

    REPLACE INSTRUMENT PANEL WIRE

  9. CHECK INSTRUMENT PANEL WIRE (SHORT TO B+)


    1. A01UZW3E01
      Text in Illustration
      *1 Front Airbag Sensor
      *2 Airbag Sensor Assembly
      *3 Engine Room Main Wire
      *4 Instrument Panel Wire
      *5 Connector C
      *a

      Front view of wire harness connector

      (to Engine Room Main Wire)

      Disconnect the instrument panel wire connector from the engine room main wire.

    2. Connect the cable to the negative (-) auxiliary battery terminal.

    3. Turn the ignition switch to ON (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      AF1-1 (+SL) - Body ground Ignition switch ON (IG) Below 1 V
      AF1-2 (-SL) - Body ground Ignition switch ON (IG) Below 1 V

    OK

    REPLACE ENGINE ROOM MAIN WIRE

    NG

    REPLACE INSTRUMENT PANEL WIRE

  10. CHECK INSTRUMENT PANEL WIRE (SHORT TO GROUND)


    1. A01UZW3E01
      Text in Illustration
      *1 Front Airbag Sensor
      *2 Airbag Sensor Assembly
      *3 Engine Room Main Wire
      *4 Instrument Panel Wire
      *5 Connector C
      *a

      Front view of wire harness connector

      (to Engine Room Main Wire)

      Disconnect the instrument panel wire connector from the engine room main wire.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      AF1-1 (+SL) - Body ground Always 1 MΩ or higher
      AF1-2 (-SL) - Body ground Always 1 MΩ or higher

    OK

    REPLACE ENGINE ROOM MAIN WIRE

    NG

    REPLACE INSTRUMENT PANEL WIRE