Supplemental Restraint Systems. Dtc B1653/35 Seat Position Airbag Sensor Circuit Malfunction

The seat position sensor circuit consists of the center airbag sensor and the seat position sensor.
DTC B1653/35 is stored when a malfunction is detected in the seat position sensor circuit.

for LHD
DTC Code	DTC Detection Condition	Trouble Area
B1653/35	When one of the following conditions is met: The center airbag sensor 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 position sensor circuit for 2 seconds. A seat position sensor malfunction. A center airbag sensor malfunction.	Floor wire Seat position sensor Center airbag sensor assembly

for RHD
DTC Code	DTC Detection Condition	Trouble Area
B1653/35	When one of the following conditions is met: The center airbag sensor 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 position sensor circuit for 2 seconds. A seat position sensor malfunction. A center airbag sensor malfunction.	No. 2 floor wire Seat position sensor Center airbag sensor assembly

WIRING DIAGRAM

Land Cruiser. Urj200, 202 Grj200 Vdj200.Supplemental Restraint Systems.Airbag System.
Dtc
B1653/35 Seat Position Airbag Sensor Circuit Malfunction

INSPECTION PROCEDURE

NOTICE:

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 (Click here).
When disconnecting the cable, some systems need to be initialized after the cable is reconnected (Click here).
After replacing the center airbag sensor assembly, refer to initialization (Click here).

1.CHECK VEHICLE CONDITION

Check vehicle condition.
Result
Result
Proceed to
for LHD
A
for RHD
B

Result
Result	Proceed to
for LHD	A
for RHD	B

Go to step 9

A

2.CHECK FOR DTC

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

Clear the DTCs (Click here).

Turn the ignition switch off.

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

Check for DTCs (Click here).
OK:
DTC B1653 is not output.
HINT:
Codes other than DTC B1653 may be output at this time, but they are not related to this check.

Go to step 3

USE SIMULATION METHOD TO CHECK (Click here)

3.CHECK CONNECTION OF CONNECTORS

Turn the ignition switch off.

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

Check that the connectors are properly connected to the center airbag sensor and the seat position sensor.
OK:
The connectors are properly connected.

CONNECT CONNECTORS PROPERLY

OK

4.CHECK CONNECTORS

Disconnect the connectors from the center airbag sensor and the seat position sensor.

Check that the connectors (on the center airbag sensor side and seat position sensor side) are not damaged.
OK:
The connectors are not deformed or damaged.

REPLACE FLOOR WIRE

OK

5.CHECK FLOOR WIRE (CENTER AIRBAG SENSOR - SEAT POSITION SENSOR)

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

Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection
Switch Condition
Specified Condition
K10-4 (LSP+) - Body ground
Ignition switch ON
Below 1 V
K10-8 (LSP-) - Body ground
Ignition switch ON
Below 1 V

w/ Side Airbag:
1. Turn the ignition switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Using a service wire, connect terminals 9 (LSP+) and 17 (LSP-) of connector B.
  NOTICE:
  Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.
4. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  K10-4 (LSP+) - K10-8 (LSP-)
  Always
  Below 1 Ω
5. Disconnect the service wire from connector B.
6. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  K10-4 (LSP+) - K10-8 (LSP-)
  Always
  1 MΩ or higher
  K10-4 (LSP+) - Body ground
  Always
  1 MΩ or higher
  K10-8 (LSP-) - Body ground
  Always
  1 MΩ or higher

w/o Side Airbag:
1. Turn the ignition switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Using a service wire, connect terminals 14 (LSP+) and 13 (LSP-) of connector B.
  NOTICE:
  Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.
4. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  K10-4 (LSP+) - K10-8 (LSP-)
  Always
  Below 1 Ω
5. Disconnect the service wire from connector B.
6. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  K10-4 (LSP+) - K10-8 (LSP-)
  Always
  1 MΩ or higher
  K10-4 (LSP+) - Body ground
  Always
  1 MΩ or higher
  K10-8 (LSP-) - Body ground
  Always
  1 MΩ or higher

REPLACE FLOOR WIRE

OK

6.CHECK SEAT POSITION SENSOR (FRONT SEAT INNER BELT LH)

Connect the connectors to the center airbag sensor and the seat position sensor.

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

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

Clear the DTCs stored in the memory (Click here).

Turn the ignition switch off.

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

Check for DTCs (Click here).
OK:
DTC B1653 is not output.
HINT:
Codes other than DTC B1653 may be output at this time, but they are not related to this check.

Go to step 7

USE SIMULATION METHOD TO CHECK (Click here)

7.REPLACE SEAT POSITION SENSOR (FRONT SEAT INNER BELT LH)

Turn the ignition switch off.

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

Replace the front seat inner belt LH (Click here).
HINT:
Perform the inspection using parts from a normally functioning vehicle if possible.

NEXT

8.CHECK CENTER AIRBAG SENSOR

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

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

Clear the DTCs (Click here).

Turn the ignition switch off.

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

Check for DTCs (Click here).
OK:
DTC B1653 is not output.
HINT:
Codes other than DTC B1653 may be output at this time, but they are not related to this check.

REPLACE CENTER AIRBAG SENSOR ASSEMBLY (Click here)

REPLACE FRONT SEAT INNER BELT ASSEMBLY LH (Click here)

9.CHECK FOR DTC

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

Clear the DTCs (Click here).

Turn the ignition switch off.

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

Check for DTCs (Click here).
OK:
DTC B1653/35 is not output.
HINT:
Codes other than DTC B1653/35 may be output at this time, but they are not related to this check.

Go to step 10

USE SIMULATION METHOD TO CHECK (Click here)

10.CHECK CONNECTION OF CONNECTORS

Turn the ignition switch off.

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

Check that the connectors are properly connected to the center airbag sensor and the seat position sensor.
OK:
The connectors are properly connected.

CONNECT CONNECTORS PROPERLY

OK

11.CHECK CONNECTORS

Disconnect the connectors from the center airbag sensor and the seat position sensor.

Check that the connectors (on the center airbag sensor side and seat position sensor side) are not damaged.
OK:
The connectors are not deformed or damaged.

REPLACE NO. 2 FLOOR WIRE

OK

12.CHECK NO. 2 FLOOR WIRE (CENTER AIRBAG SENSOR - SEAT POSITION SENSOR)

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

Turn the ignition switch to ON.

Measure the voltage according the value(s) in the table below.
Standard Voltage:
Tester Connection
Switch Condition
Specified Condition
L33-4 (RSP+) - Body ground
Ignition switch ON
Below 1 V
L33-8 (RSP-) - Body ground
Ignition switch ON
Below 1 V

w/ Side Airbag:
1. Turn the ignition switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Using a service wire, connect terminals 16 (RSP+) and 24 (RSP-) of connector B.
  NOTICE:
  Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.
4. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  L33-4 (RSP+) - L33-8 (RSP-)
  Always
  Below 1 Ω
5. Disconnect the service wire from connector B.
6. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  L33-4 (RSP+) - L33-8 (RSP-)
  Always
  1 MΩ or higher
  L33-4 (RSP+) - Body ground
  Always
  1 MΩ or higher
  L33-8 (RSP-) - Body ground
  Always
  1 MΩ or higher

w/o Side Airbag:
1. Turn the ignition switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Using a service wire, connect terminals 12 (RSP+) and 13 (RSP-) of connector B.
  NOTICE:
  Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.
4. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  L33-4 (RSP+) - L33-8 (RSP-)
  Always
  Below 1 Ω
5. Disconnect the service wire from connector B.
6. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  L33-4 (RSP+) - L33-8 (RSP-)
  Always
  1 MΩ or higher
  L33-4 (RSP+) - Body ground
  Always
  1 MΩ or higher
  L33-8 (RSP-) - Body ground
  Always
  1 MΩ or higher

REPLACE NO. 2 FLOOR WIRE

OK

13.CHECK SEAT POSITION SENSOR (FRONT SEAT INNER BELT RH)

Connect the connectors to the center airbag sensor and the seat position sensor.

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

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

Clear the DTCs stored (Click here).

Turn the ignition switch off.

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

Check for DTCs (Click here).
OK:
DTC B1653/35 is not output.
HINT:
Codes other than DTC B1653/35 may be output at this time, but they are not related to this check.

Go to step 14

USE SIMULATION METHOD TO CHECK (Click here)

14.REPLACE SEAT POSITION SENSOR

Turn the ignition switch off.

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

Replace the seat position sensor (Click here).
HINT:
Perform inspection using parts from a normal vehicle if possible.

NEXT

15.CHECK CENTER AIRBAG SENSOR

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

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

Clear the DTCs (Click here).

Turn the ignition switch off.

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

Check for DTCs (Click here).
OK:
DTC B1653/35 is not output.
HINT:
Codes other than DTC B1653/35 may be output at this time, but they are not related to this check.

REPLACE CENTER AIRBAG SENSOR ASSEMBLY (Click here)

REPLACE FRONT SEAT INNER BELT ASSEMBLY RH

Tester Connection	Switch Condition	Specified Condition
K10-4 (LSP+) - Body ground	Ignition switch ON	Below 1 V
K10-8 (LSP-) - Body ground	Ignition switch ON	Below 1 V

Tester Connection	Condition	Specified Condition
K10-4 (LSP+) - K10-8 (LSP-)	Always	Below 1 Ω