AIRBAG SYSTEM, Diagnostic DTC:B1925/78,B1926/78,B1927/78 and B1928/78

DTC Code DTC Name
B1925/78 Short in Rear Pretensioner Squib LH Circuit
B1926/78 Open in Rear Pretensioner Squib LH Circuit
B1927/78 Short to GND in Rear Pretensioner Squib LH Circuit
B1928/78 Short to B+ in Rear Pretensioner Squib LH Circuit

DESCRIPTION

The rear pretensioner squib LH circuit consists of the center airbag sensor and the rear No. 1 seat outer belt LH.

This circuit instructs the SRS to deploy when deployment conditions are met.

These DTCs are stored when a malfunction is detected in the rear pretensioner squib LH circuit.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Test Mode / Check Mode

B1925/78

Short in Rear Pretensioner Squib LH Circuit

One of the following conditions is met:

  • The center airbag sensor detects a line short circuit signal 5 times in the rear pretensioner squib LH circuit during the primary check.

  • A rear pretensioner squib LH malfunction.

  • A center airbag sensor malfunction.

  • No. 2 floor wire

  • Rear No. 1 seat outer belt assembly LH (Rear pretensioner squib LH)

  • Center airbag sensor assembly

*2

B1926/78

Open in Rear Pretensioner Squib LH Circuit

One of the following conditions is met:

  • The center airbag sensor detects an open circuit signal in the rear pretensioner squib LH circuit for 2 seconds.

  • A rear pretensioner squib LH malfunction.

  • A center airbag sensor malfunction.

  • No. 2 floor wire

  • Rear No. 1 seat outer belt assembly LH (Rear pretensioner squib LH)

  • Center airbag sensor assembly

*2

B1927/78

Short to GND in Rear Pretensioner Squib LH Circuit

One of the following conditions is met:

  • The center airbag sensor detects a short circuit to ground signal in the rear pretensioner squib LH circuit for 0.5 seconds.

  • A rear pretensioner squib LH malfunction.

  • A center airbag sensor malfunction.

  • No. 2 floor wire

  • Rear No. 1 seat outer belt assembly LH (Rear pretensioner squib LH)

  • Center airbag sensor assembly

*2

B1928/78

Short to B+ in Rear Pretensioner Squib LH Circuit

One of the following conditions is met:

  • The center airbag sensor detects a short circuit to B+ signal in the rear pretensioner squib LH circuit for 0.5 seconds.

  • A rear pretensioner squib LH malfunction.

  • A center airbag sensor malfunction.

  • No. 2 floor wire

  • Rear No. 1 seat outer belt assembly LH (rear pretensioner squib LH)

  • Center airbag sensor assembly

*2

WIRING DIAGRAM

C174615E79

CAUTION / NOTICE / HINT

Note:

  • After turning the engine switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work (Click here).

  • When disconnecting the cable from the negative (-) battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected (Click here).

Tip:

To perform the simulation method, enter the check mode (signal check) with the intelligent tester (Click here), and then wiggle each connector of the airbag system or drive the vehicle on various types of road (Click here).

PROCEDURE

  1. CHECK REAR NO. 1 SEAT OUTER BELT LH (REAR PRETENSIONER SQUIB LH)

    1. C213957C04

      *1

      Rear Pretensioner Squib LH

      *2

      Center Airbag Sensor

      *3

      Connector C

      *4

      SST

      *a

      Front view of wire harness connector

      (to Rear Pretensioner Squib LH)

      Turn the engine switch off.

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

    3. Disconnect the connectors from the rear No. 1 seat outer belt LH.

    4. Connect the white wire side of SST (resistance: 2.1 Ω) to connector C.

      CAUTION:

      Never connect the tester to the rear No. 1 seat outer belt LH (rear pretensioner squib LH) for measurement, as this may lead to a serious injury due to airbag deployment.

      Note:

      • Do not forcibly insert SST into the terminals of the connector when connecting SST.

      • Insert SST straight into the terminals of the connector.

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

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

    7. Clear the DTCs.

      Click here

      Body Electrical > SRS Airbag > Clear DTCs

    8. Turn the engine switch off.

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

    10. Check for DTCs.

      Click here

      Body Electrical > SRS Airbag > Trouble Codes

      OK

      DTC B1925, B1926, B1927 or B1928 is not output.

      Tip:

      Codes other than DTC B1925, B1926, B1927 and B1928 may be output at this time, but they are not related to this check.

      Result

      Result

      OK

      NG

    09843-18061

    OK

    REPLACE REAR NO. 1 SEAT OUTER BELT ASSEMBLY LH

    Click here

    NG

  2. CHECK CONNECTOR

    1. Turn the engine switch off.

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

    3. Disconnect SST from connector C.

    4. C214774C07

      *1

      Rear Pretensioner Squib LH

      *2

      Center Airbag Sensor

      Check that the No. 2 floor wire connector (on the rear No. 1 seat outer belt LH side) is not damaged.

      OK

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

      Result

      Result

      OK

      NG
    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

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

    1. C213958C03

      *1

      Rear Pretensioner Squib LH

      *2

      No. 2 Floor Wire

      *3

      Center Airbag Sensor

      *4

      Connector C

      *a

      Front view of wire harness connector

      (to Rear Pretensioner Squib LH)

      Disconnect the connectors from the center airbag sensor.

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

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      R29-1 (RL+) - Body ground

      Engine switch on (IG)

      Below 1 V

      R29-2 (RL-) - Body ground

      Engine switch on (IG)

      Below 1 V

    4. Turn the engine switch off.

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

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      R29-1 (RL+) - R29-2 (RL-)

      Always

      Below 1 Ω

    7. Release the activation prevention mechanism built into connector B.

      Click here

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      R29-1 (RL+) - R29-2 (RL-)

      Always

      1 MΩ or higher

      R29-1 (RL+) - Body ground

      Always

      1 MΩ or higher

      R29-2 (RL-) - Body ground

      Always

      1 MΩ or higher

      Result

      Result

      OK

      NG
    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  4. CHECK CENTER AIRBAG SENSOR

    1. C146259C07

      *1

      Rear Pretensioner Squib LH

      *2

      Center Airbag Sensor

      Connect the connectors to the rear No. 1 seat outer belt LH and the center airbag sensor.

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

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

    4. Clear the DTCs.

      Click here

      Body Electrical > SRS Airbag > Clear DTCs

    5. Turn the engine switch off.

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

    7. Check for DTCs.

      Click here

      Body Electrical > SRS Airbag > Trouble Codes

      OK

      DTC B1925, B1926, B1927 or B1928 is not output.

      Tip:

      Codes other than DTC B1925, B1926, B1927 or B1928 may be output at this time, but they are not related to this check.

      Result

      Result

      OK

      NG
    OK

    USE SIMULATION METHOD TO CHECK

    Click here

    NG

    REPLACE CENTER AIRBAG SENSOR ASSEMBLY

    Click here