Dtc B1656/38 Seat Belt Buckle Switch Lh Circuit Malfunction


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK FOR DTC

CHECK CONNECTION OF CONNECTORS

CHECK CONNECTORS

CHECK NO. 2 FLOOR WIRE (CENTER AIRBAG SENSOR - FRONT SEAT INNER BELT LH)

CHECK FRONT SEAT INNER BELT LH (SEAT BELT BUCKLE SWITCH)

REPLACE FRONT SEAT INNER BELT ASSEMBLY LH

CHECK CENTER AIRBAG SENSOR

DTC B1656/38 Seat Belt Buckle Switch LH Circuit Malfunction


DESCRIPTION

The seat belt buckle switch LH circuit consists of the center airbag sensor and front seat inner belt LH.
DTC B1656/38 is stored when a malfunction is detected in the seat belt buckle switch LH circuit.

DTC Code
DTC Detection Condition
Trouble Area
B1656/38
One of the following conditions is met:
  1. The center airbag sensor detects a line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in the seat belt buckle switch LH circuit for 2 seconds.
  2. A front seat inner belt LH malfunction.
  3. A center airbag sensor malfunction.
  1. No. 2 floor wire
  2. Front seat inner belt assembly LH (Seat belt buckle switch LH)
  3. Center airbag sensor assembly

WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Supplemental Restraint Systems.Airbag System. Dtc B1656/38 Seat Belt Buckle Switch Lh Circuit Malfunction


INSPECTION PROCEDURE

NOTICE:
  1. After turning the ignition 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 (LandCruiser RM000003YMD00TX.html).
  2. When disconnecting the cable from the negative (-) battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected (LandCruiser RM000003YMF011X.html).
1.CHECK FOR DTC

  1. Turn the ignition switch to ON.

  1. Clear the DTCs (LandCruiser RM000000XFE0NGX.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 (LandCruiser RM000000XFE0NGX.html).

    OK:
    DTC B1656 is not output.
    HINT:
    Codes other than DTC B1656 may be output at this time, but they are not related to this check.


NG
Go to step 2
OK

USE SIMULATION METHOD TO CHECK (LandCruiser RM000000XFD0N3X.html)

2.CHECK CONNECTION OF CONNECTORS

  1. Turn the ignition switch off.

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

  1. Check that the connectors are properly connected to the center airbag sensor and front seat inner belt LH.

    OK:
    The connectors are properly connected.


NG
CONNECT CONNECTORS PROPERLY
OK


3.CHECK CONNECTORS

  1. Disconnect the connectors from the center airbag sensor and front seat inner belt LH.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Supplemental Restraint Systems.Airbag System. Dtc B1656/38 Seat Belt Buckle Switch Lh Circuit Malfunction

  1. Check that the connectors (on the center airbag sensor side and front seat inner belt LH side) are not damaged.

    OK:
    The connectors are not deformed or damaged.
    Text in Illustration
    *1
    		Front Seat Inner Belt LH
    *2
    		Center Airbag Sensor


NG
REPLACE NO. 2 FLOOR WIRE
OK


4.CHECK NO. 2 FLOOR WIRE (CENTER AIRBAG SENSOR - FRONT SEAT INNER BELT LH)


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


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Supplemental Restraint Systems.Airbag System. Dtc B1656/38 Seat Belt Buckle Switch Lh Circuit Malfunction


    Text in Illustration
    *1
    		Front Seat Inner Belt LH
    		*2
    		Center Airbag Sensor
    *3
    		No. 2 Floor Wire
    		*4
    		Connector C
    *5
    		Connector B
    		-
    		-
    *a
    		Front view of wire harness connector
    (to Front Seat Inner Belt LH)
    		*b
    		Rear view of wire harness connector
    (to Center Airbag Sensor)

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    R48-2 (LBE+) - Body ground
    		Ignition switch ON
    		Below 1 V
    R48-1 (LBE-) - Body ground
    		Ignition switch ON
    		Below 1 V

  1. Turn the ignition switch off.

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

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    R48-2 (LBE+) - R1-11 (LBE+)
    		Always
    		Below 1 Ω
    R48-1 (LBE-) - R1-12 (LBE-)
    		Always
    		Below 1 Ω
    R48-2 (LBE+) - Body ground
    		Always
    		1 MΩ or higher
    R48-1 (LBE-) - Body ground
    		Always
    		1 MΩ or higher


NG
REPLACE NO. 2 FLOOR WIRE
OK


5.CHECK FRONT SEAT INNER BELT LH (SEAT BELT BUCKLE SWITCH)


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Supplemental Restraint Systems.Airbag System. Dtc B1656/38 Seat Belt Buckle Switch Lh Circuit Malfunction

  1. Connect the connectors to the center airbag sensor and front seat inner belt LH.

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

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

  1. Clear the DTCs (LandCruiser RM000000XFE0NGX.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 (LandCruiser RM000000XFE0NGX.html).

    OK:
    DTC B1656 is not output.
    HINT:
    Codes other than DTC B1656 may be output at this time, but they are not related to this check.
    Text in Illustration
    *1
    		Front Seat Inner Belt LH
    *2
    		Center Airbag Sensor


NG
Go to step 6
OK

USE SIMULATION METHOD TO CHECK (LandCruiser RM000000XFD0N3X.html)

6.REPLACE FRONT SEAT INNER BELT ASSEMBLY LH

  1. Turn the ignition switch off.

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

  1. Replace the front seat inner belt LH (LandCruiser RM000003RQO025X.html).

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

NEXT


7.CHECK CENTER AIRBAG SENSOR


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Supplemental Restraint Systems.Airbag System. Dtc B1656/38 Seat Belt Buckle Switch Lh Circuit Malfunction

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

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

  1. Clear the DTCs (LandCruiser RM000000XFE0NGX.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 (LandCruiser RM000000XFE0NGX.html).

    OK:
    DTC B1656 is not output.
    HINT:
    Codes other than DTC B1656 may be output at this time, but they are not related to this check.
    Text in Illustration
    *1
    		Front Seat Inner Belt LH
    *2
    		Center Airbag Sensor


NG
REPLACE CENTER AIRBAG SENSOR ASSEMBLY (LandCruiser RM000003YQB01BX.html)
OK

REPLACE FRONT SEAT INNER BELT ASSEMBLY LH (LandCruiser RM000003RQO025X.html)