AIRBAG SYSTEM, Diagnostic DTC:B1855, B1856, B1857, B1858

DTC Code DTC Name
B1855 Short in Rear Side Squib LH Circuit
B1856 Open in Rear Side Squib LH Circuit
B1857 Short to GND in Rear Side Squib LH Circuit
B1858 Short to B+ in Rear Side Squib LH Circuit

DESCRIPTION

The rear side squib LH circuit consists of the airbag ECU assembly and rear seat airbag assembly LH.

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

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

DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Test Mode / Check Mode
B1855 Short in Rear Side Squib LH Circuit

One of the following conditions is met:


  • The airbag ECU assembly detects a line short circuit signal 5 times in the rear side squib LH circuit during the primary check.

  • A rear seat airbag assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • Floor wire

  • Rear seat wire LH*

  • Rear seat airbag assembly LH

  • Airbag ECU assembly

 Comes on Applicable
B1856 Open in Rear Side Squib LH Circuit

One of the following conditions is met:


  • The airbag ECU assembly detects an open circuit signal in the rear side squib LH circuit for 2 seconds.

  • A rear seat airbag assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • Floor wire

  • Rear seat wire LH*

  • Rear seat airbag assembly LH

  • Airbag ECU assembly

 Comes on Applicable
B1857 Short to GND in Rear Side Squib LH Circuit

One of the following conditions is met:


  • The airbag ECU assembly detects a short circuit to ground signal in the rear side squib LH circuit for 0.5 seconds.

  • A rear seat airbag assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • Floor wire

  • Rear seat wire LH*

  • Rear seat airbag assembly LH

  • Airbag ECU assembly

 Comes on Applicable
B1858 Short to B+ in Rear Side Squib LH Circuit

One of the following conditions is met:


  • The airbag ECU assembly detects a short circuit to B+ signal in the rear side squib LH circuit for 0.5 seconds.

  • A rear seat airbag assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • Floor wire

  • Rear seat wire LH*

  • Rear seat airbag assembly LH

  • Airbag ECU assembly

 Comes on Applicable

*: for Power Seat

WIRING DIAGRAM

Figure 1. for Fixed Seat Type:

B004W3LE54
*a Rear Seat Airbag Assembly LH
*b Airbag ECU Assembly

Figure 2. for Power Seat:

B004WRZE12
*a Rear Seat Airbag Assembly LH
*b Airbag ECU Assembly

CAUTION / NOTICE / HINT

Note


  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

    Click here

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

    Click here

Tech Tips

To perform the simulation method, enter check mode (signal check) with the GTS (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 VEHICLE CONDITION


    1. Check vehicle condition.

      Result
      Proceed to
      for Fixed Seat Type
      for Power Seat

    for Power Seat

    CHECK CONNECTORS Click here

    for Fixed Seat Type

  2. CHECK CONNECTORS


    1. B004WUYC32
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Floor Wire

      Turn the power switch off.

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

    3. Check that the connectors are properly connected to the rear seat airbag assembly LH and airbag ECU assembly.

      OK
      The connectors are properly connected.

      Tech Tips

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

    4. Disconnect the connectors from the rear seat airbag assembly LH and airbag ECU assembly.

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

      OK
      The terminals are not deformed or damaged.

    6. Check that the short springs of the activation prevention mechanism of the floor wire connector are not deformed or damaged.

      OK
      The short springs are not deformed or damaged.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FLOOR WIRE

    OK

  3. CHECK REAR SEAT AIRBAG ASSEMBLY LH


    1. B004URZC19
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 SST
      *a

      Front view of wire harness connector

      (to Rear Seat Airbag Assembly LH)

      Connect the connector to the airbag ECU assembly.

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

      CAUTION:

      Never connect the tester to the rear seat airbag assembly 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.

      SST
      09843-18061

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

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

    5. Clear the DTCs.

      Click here


      Body Electrical > SRS Airbag > Clear DTCs

    6. Turn the power switch off.

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

    8. Check for DTCs.

      Click here


      Body Electrical > SRS Airbag > Trouble Codes
      Result
      Proceed to
      DTC B1855, B1856, B1857 and B1858 are not output.
      DTC B1855, B1856, B1857 or B1858 is output.

      Tech Tips

      Codes other than DTC B1855, B1856, B1857 and B1858 may be output at this time, but they are not related to this check.

    9. Turn the power switch off.

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

    11. Disconnect SST from connector C.


    DTC B1855, B1856, B1857 and B1858 are not output.

    REPLACE REAR SEAT AIRBAG ASSEMBLY LH Click here

    DTC B1855, B1856, B1857 or B1858 is output.

  4. CHECK FLOOR WIRE


    1. B004U4WC07
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Floor Wire
      *a

      Front view of wire harness connector

      (to Rear Seat Airbag Assembly LH)
      B004SZX Release the activation prevention mechanism

      Disconnect the floor wire from the airbag ECU assembly.

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


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

      2. Turn the power switch on (IG).

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

        Standard Voltage
        Tester Connection Condition Specified Condition
        L107-1 (SRL+) - Body ground Power switch on (IG) Below 1 V
        L107-2 (SRL-) - Body ground Power switch on (IG) Below 1 V

      4. Turn the power switch off.

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

    3. Check for an open in the circuit.


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

        Standard Resistance
        Tester Connection Condition Specified Condition
        L107-1 (SRL+) - L107-2 (SRL-) Always Below 1 Ω

    4. 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
        L107-1 (SRL+) - Body ground Always 1 MΩ or higher
        L107-2 (SRL-) - Body ground Always 1 MΩ or higher

    5. 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
        L107-1 (SRL+) - L107-2 (SRL-) Always 1 MΩ or higher

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

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FLOOR WIRE

    OK

  5. CHECK DTC


    1. B004VGAC11
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag ECU Assembly

      Connect the connectors to the rear seat airbag assembly LH and airbag ECU assembly.

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

    3. Turn the power 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 power switch off.

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

    7. Check for DTCs.

      Click here


      Body Electrical > SRS Airbag > Trouble Codes
      Result
      Proceed to
      DTC B1855, B1856, B1857 and B1858 are not output
      DTC B1855, B1856, B1857 or B1858 is output

      Tech Tips

      Codes other than DTC B1855, B1856, B1857 and B1858 may be output at this time, but they are not related to this check.


    DTC B1855, B1856, B1857 and B1858 are not output

    USE SIMULATION METHOD TO CHECK Click here

    DTC B1855, B1856, B1857 or B1858 is output

    REPLACE AIRBAG ECU ASSEMBLY Click here

  6. CHECK CONNECTORS


    1. B004YBSC03
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Rear Seat Wire LH
      *4 Floor Wire

      Turn the power switch off.

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

    3. Check that the connectors are properly connected to the rear seat airbag assembly LH and airbag ECU assembly.

      OK
      The connectors are properly connected.

      Tech Tips

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

    4. Disconnect the connectors from the rear seat airbag assembly RH and airbag ECU assembly.

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

      OK
      The terminals are not deformed or damaged.

    6. Check that the short springs of the activation prevention mechanism of the rear seat wire connector and rear seat airbag assembly LH connector are not deformed or damaged.

      OK
      The short springs are not deformed or damaged.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE REAR SEAT WIRE LH OR FLOOR WIRE

    OK

  7. CHECK REAR SEAT AIRBAG ASSEMBLY LH


    1. B004WZWC01
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 SST
      *a

      Front view of wire harness connector

      (to Rear Seat Airbag Assembly LH)

      Connect the connector to the airbag ECU assembly.

    2. Connect the red wire side of SST (resistance: 2.1 Ω) to connector E.

      CAUTION:

      Never connect the tester to the rear seat airbag assembly 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.

      SST
      09843-18061

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

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

    5. Clear the DTCs.

      Click here


      Body Electrical > SRS Airbag > Clear DTCs

    6. Turn the power switch off.

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

    8. Check for DTCs.

      Click here


      Body Electrical > SRS Airbag > Trouble Codes
      Result
      Proceed to
      DTC B1855, B1856, B1857 and B1858 are not output.
      DTC B1855, B1856, B1857 or B1858 is output.

      Tech Tips

      Codes other than DTC B1855, B1856, B1857 and B1858 may be output at this time, but they are not related to this check.

    9. Turn the power switch off.

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

    11. Disconnect SST from connector E.


    DTC B1855, B1856, B1857 and B1858 are not output.

    REPLACE REAR SEAT AIRBAG ASSEMBLY LH Click here

    DTC B1855, B1856, B1857 or B1858 is output.

  8. CHECK REAR SEAT AIRBAG ASSEMBLY LH CIRCUIT


    1. B004SC1C03
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Rear Seat Wire LH
      *4 Floor Wire
      *a

      Front view of wire harness connector

      (to Rear Seat Airbag Assembly LH)
      B004SZX Release the activation prevention mechanism

      Disconnect the floor wire from the airbag ECU assembly.

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


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

      2. Turn the power switch on (IG).

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

        Standard Voltage
        Tester Connection Condition Specified Condition
        R51-1 (SRL+) - Body ground Power switch on (IG) Below 1 V
        R51-2 (SRL-) - Body ground Power switch on (IG) Below 1 V

      4. Turn the power switch off.

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

    3. Check for an open in the circuit.


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

        Standard Resistance
        Tester Connection Condition Specified Condition
        R51-1 (SRL+) - R51-2 (SRL-) Always Below 1 Ω

    4. 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
        R51-1 (SRL+) - Body ground Always 1 MΩ or higher
        R51-2 (SRL-) - Body ground Always 1 MΩ or higher

    5. 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
        R51-1 (SRL+) - R51-2 (SRL-) Always 1 MΩ or higher

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

      Result
      Proceed to
      OK
      NG

    NG

    CHECK FLOOR WIRE Click here

    OK

  9. CHECK DTC


    1. B004TI6C04
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag ECU Assembly

      Connect the connectors to the rear seat airbag assembly LH and airbag ECU assembly.

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

    3. Turn the power 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 power switch off.

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

    7. Check for DTCs.

      Click here


      Body Electrical > SRS Airbag > Trouble Codes
      Result
      Proceed to
      DTC B1855, B1856, B1857 and B1858 are not output
      DTC B1855, B1856, B1857 or B1858 is output

      Tech Tips

      Codes other than DTC B1855, B1856, B1857 and B1858 may be output at this time, but they are not related to this check.


    DTC B1855, B1856, B1857 and B1858 are not output

    USE SIMULATION METHOD TO CHECK Click here

    DTC B1855, B1856, B1857 or B1858 is output

    REPLACE AIRBAG ECU ASSEMBLY Click here

  10. CHECK FLOOR WIRE


    1. B004U6AC02
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Floor Wire
      *4 Rear Seat Wire LH
      *a

      Front view of wire harness connector

      (to Rear Seat Airbag Assembly LH)
      B004SZX Release the activation prevention mechanism

      Disconnect the floor wire from the airbag ECU assembly.

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


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

      2. Turn the power switch on (IG).

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

        Standard Voltage
        Tester Connection Condition Specified Condition
        LR 10-1 (SRL+) - Body ground Power switch on (IG) Below 1 V
        LR 10-2 (SRL-) - Body ground Power switch on (IG) Below 1 V

      4. Turn the power switch off.

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

    3. Check for an open in the circuit.


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

        Standard Resistance
        Tester Connection Condition Specified Condition
        LR 10-1 (SRL+) - LR 10-2 (SRL-) Always Below 1 Ω

    4. 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
        LR 10-1 (SRL+) - Body ground Always 1 MΩ or higher
        LR 10-2 (SRL-) - Body ground Always 1 MΩ or higher

    5. 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
        LR 10-1 (SRL+) - LR 10-2 (SRL-) Always 1 MΩ or higher

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

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE REAR SEAT WIRE LH

    NG

    REPLACE FLOOR WIRE