Toyota Sienna Quiz
Supplemental restraint system

Seat Belt Buckle Switch LH Circuit Malfunction

In this manual: Supplemental restraint system
Introduction — 55Service specifications — 7Maintenance — 7Engine — 264U151e automatic transaxle — 108Transfer — 19Propeller shaft — 8Drive shaft — 14Differential — 16Axle — 18Suspension — 37Tire and wheel — 54Brake control — 141Parking brake — 16Steering Column — 11Power steering — 18Air conditioning — 106Supplemental restraint system — 146Seat belt — 22Theft deterrent — 14Engine immobiliser — 17Cruise control — 65Lighting — 61Wiper and washer — 13Door lock — 42Meter — 28Audio / visual — 94Navigation — 108Park assist / monitoring — 33Horn — 5Garage door opener — 42GR-FE Engine control system — 126Supplemental restraint system — 147Other system — 14Windshield / windowglass — 43Mirror — 23Instrument panel — 6Seat belt — 22Seat — 92Engine hood / door — 104Exterior — 39Interior — 5Sliding roof — 9Multiplex communication — 18Can communication — 23
58steps
~348min
4/5difficulty
Done 0 of 58

DTC B0126/27 Seat Belt Buckle Switch LH Circuit Malfunction

DESCRIPTION

The seat belt buckle switch LH circuit consists of the center airbag sensor assembly and the front seat inner belt assembly LH.

DTC B0126/27 is recorded when a malfunction is detected in the seat belt buckle switch LH circuit

DTC No.

DTC Detecting Condition

Trouble Area

B0126/27
  • The center 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 seat belt buckle switch LH circuit for 2 seconds.
  • Front seat inner belt assembly LH malfunction
  • Center airbag sensor assembly malfunction
  • Front seat inner belt assembly LH (Seat belt buckle switch LH)
  • Center airbag sensor assembly
  • Floor wire

WIRING DIAGRAM

WIRING DIAGRAM

INSPECTION PROCEDURE

1 CHECK DTC

CHECK DTC
  1. Turn the ignition switch to the ON position, and wait for at least 60 seconds.
  2. Clear the DTCs stored in memory (5).
  3. Turn the ignition switch to the LOCK position.
  4. Turn the ignition switch to the ON position, and wait for at least 60 seconds.
  5. Check the DTCs (5).

OK: DTC B0126/27 is not output. HINT: Codes other than code B0126/27 may be output at this time, but they are not related to this check.

Go to step 2

USE SIMULATION METHOD TO CHECK

2 CHECK CONNECTION OF CONNECTORS

  1. Turn the ignition switch to the LOCK position.
  2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
  3. Check that the connectors are properly connected to the center airbag sensor assembly and the front seat inner belt assembly LH.

OK: The connectors are connected.

CONNECT CONNECTORS

3 CHECK VEHICLE

  1. Check the front driver seat type.

Result

Result

Go to step 11

4 CHECK FLOOR WIRE (OPEN)

CHECK FLOOR WIRE (OPEN)
  1. Disconnect the connectors from the center airbag sensor assembly and the front seat inner belt assembly LH.
  2. w/ Side airbag: Using a service wire, connect A20-19 (LBE+) and A20-2 (LBE-) of connector "B".

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

  • w/o Side airbag: Using a service wire, connect A20-11 (LBE+) and A20-6 (LBE-) of connector "B".

    • NOTICE: Do not forcibly insert a service wire into the terminals of the connector when connecting.
  • Measure the resistance according to the value(s) in the table below.

    • Standard resistance

    Standard resistance

    REPAIR OR REPLACE FLOOR WIRE

    5 CHECK FLOOR WIRE (SHORT TO B+)

    Check floor wire (short to b+)
    1. Disconnect the service wire from connector "B".
    2. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
    3. Turn the ignition switch to the ON position.
    4. Measure the voltage according to the value(s) in the table below.

    Standard voltage

    Standard voltage

    REPAIR OR REPLACE FLOOR WIRE

    6 CHECK FLOOR WIRE (SHORT TO GROUND)

    CHECK FLOOR WIRE (SHORT TO GROUND)
    1. Turn the ignition switch to the LOCK position.
    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

    CHECK FLOOR WIRE (SHORT TO GROUND)

    REPAIR OR REPLACE FLOOR WIRE

    7 CHECK FLOOR WIRE (SHORT)

    CHECK FLOOR WIRE (SHORT)
    1. Measure the voltage according to the value(s) in the table below.

    Standard resistance

    Standard resistance

    REPAIR OR REPLACE FLOOR WIRE

    8 CHECK FRONT SEAT INNER BELT ASSEMBLY LH

    CHECK FRONT SEAT INNER BELT ASSEMBLY LH
    1. Connect the connectors to the front seat inner belt assembly LH and the center airbag sensor assembly.
    2. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
    3. Turn the ignition switch to the ON position, and wait for at least 60 seconds.
    4. Clear the DTCs stored in memory (5).
    5. Turn the ignition switch to the LOCK position.
    6. Turn the ignition switch to the ON position, and wait for at least 60 seconds.
    7. Check the DTCs (5).

    OK: DTC B0126/27 is not output. HINT: Codes other than code B0126/27 may be output at this time, but they are not related to this check.

    Go to step 9

    USE SIMULATION METHOD TO CHECK

    9 REPLACE FRONT SEAT INNER BELT ASSEMBLY LH

    1. Turn the ignition switch to the LOCK position.
    2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
    3. Replace the front seat inner belt assembly LH.

    HINT: Perform the inspection using parts from a normal vehicle if possible.

    10 CHECK CENTER AIRBAG SENSOR ASSEMBLY

    CHECK CENTER AIRBAG SENSOR ASSEMBLY
    1. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
    2. Turn the ignition switch to the ON position, and wait for at least 60 seconds.
    3. Clear the DTCs stored in memory (5).
    4. Turn the ignition switch to the LOCK position.
    5. Turn the ignition switch to the ON position, and wait for at least 60 seconds.
    6. Check the DTCs (5).

    OK: DTC B0126/27 is output. HINT: Codes other than code B0126/27 may be output at this time, but they are not related to this check.

    REPLACE CENTER AIRBAG SENSOR ASSEMBLY

    END

    11 CHECK FLOOR WIRE (OPEN)

    CHECK FLOOR WIRE (OPEN)
    1. Disconnect the connectors from the center airbag sensor assembly and the front seat inner belt assembly LH.
    2. w/ Side airbag: Using a service wire, connect A20-19 (LBE+) and A20-2 (LBE-) of connector "B".

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

  • w/o Side airbag: Using a service wire, connect A20-11 (LBE+) and A20-6 (LBE-) of connector "B".

    • NOTICE: Do not forcibly insert a service wire into the terminals of the connector when connecting.
  • Measure the resistance according to the value(s) in the table below.

    • Standard resistance

    Standard resistance

    REPAIR OR REPLACE FLOOR WIRE

    12 CHECK FLOOR WIRE (SHORT TO B+)

    CHECK FLOOR WIRE (SHORT TO B+)
    1. Disconnect the service wire from connector "B".
    2. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
    3. Turn the ignition switch to the ON position.
    4. Measure the voltage according to the value(s) in the table below.

    Standard voltage

    Standard voltage

    REPAIR OR REPLACE FLOOR WIRE

    13 CHECK FLOOR WIRE (SHORT TO GROUND)

    CHECK FLOOR WIRE (SHORT TO GROUND)
    1. Turn the ignition switch to the LOCK position.
    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

    Standard resistance

    REPAIR OR REPLACE FLOOR WIRE

    14 CHECK FLOOR WIRE (SHORT)

    CHECK FLOOR WIRE (SHORT)
    1. Measure the resistance according to the value(s) in the table below.

    Standard resistance

    Standard resistance

    REPAIR OR REPLACE FLOOR WIRE

    15 CHECK FRONT SEAT INNER BELT ASSEMBLY LH

    CHECK FRONT SEAT INNER BELT ASSEMBLY LH
    1. Connect the connectors to the front seat inner belt assembly LH and the center airbag sensor assembly.
    2. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
    3. Turn the ignition switch to the ON position, and wait for at least 60 seconds.
    4. Clear the DTCs stored in memory (5).
    5. Turn the ignition switch to the LOCK position.
    6. Turn the ignition switch to the ON position, and wait for at least 60 seconds.
    7. Check the DTCs (5).

    OK: DTC B0126/27 is not output. HINT: Codes other than code B0126/27 may be output at this time, but they are not related to this check.

    Go to step 16

    USE SIMULATION METHOD TO CHECK

    16 REPLACE FRONT SEAT INNER BELT ASSEMBLY LH

    1. Turn the ignition switch to the LOCK position.
    2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
    3. Replace the front seat inner belt assembly LH.

    HINT: Perform the inspection using parts from a normal vehicle if possible.

    17 CHECK CENTER AIRBAG SENSOR ASSEMBLY

    CHECK CENTER AIRBAG SENSOR ASSEMBLY
    1. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
    2. Turn the ignition switch to the ON position, and wait for at least 60 seconds.
    3. Clear the DTCs stored in memory (5).
    4. Turn the ignition switch to the LOCK position.
    5. Turn the ignition switch to the ON position, and wait for at least 60 seconds.
    6. Check the DTCs (5).

    OK: DTC B0126/27 is not output. HINT: Codes other than code B0126/27 may be output at this time, but they are not related to this check.

    REPLACE CENTER AIRBAG SENSOR ASSEMBLY

    END

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