DTC B1656/38: Seat Belt Buckle Switch LH Circuit Malfunction: Procedure

1. Turn the ignition switch off.
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. 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: Go to next step 

1. Disconnect the connectors from the center airbag sensor and front seat inner belt LH.
2. Check that the connectors (on the center airbag sensor side and front seat inner belt LH side) are not damaged. Refer to DIAGNOSIS SYSTEM .

   OK

   The connectors are not deformed or damaged.

   Fig 1: Checking Connectors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

   *1	Front Seat Inner Belt LH
   *2	Center Airbag Sensor

NG → REPLACE FLOOR WIRE 

OK: Go to next step 

1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
   Fig 2: Checking Floor Wire (Center Airbag Sensor - Front Seat Inner Belt LH)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

   *1	Front Seat Inner Belt LH	*2	Center Airbag Sensor
   *3	Floor Wire	*4	Connector C
   *5	Connector B	*6	Service Wire
   *a	Front view of wire harness connector (to Front Seat Inner Belt LH)	*b	Rear view of wire harness connector (to Center Airbag Sensor)

2. Turn the ignition switch to ON.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   H15-2 (LBE+) - Body ground	Ignition switch ON	Below 1 V
   H15-1 (LBE-) - Body ground	Ignition switch ON	Below 1 V

4. Turn the ignition switch off.
5. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
6. Using a service wire, connect terminals 11 (LBE+) and 12 (LBE-) of connector B.
   NOTE:

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

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H15-2 (LBE+) - H15-1 (LBE-)	Always	Below 1 Ω

8. Disconnect the service wire from connector B.
9. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H15-2 (LBE+) - H15-1 (LBE-)	Always	1 MΩ or higher
   H15-2 (LBE+) - Body ground	Always	1 MΩ or higher
   H15-1 (LBE-) - Body ground	Always	1 MΩ or higher

NG → REPLACE FLOOR WIRE 

OK: Go to next step 

1. Connect the connector to the center airbag sensor and front seat inner belt LH.
   Fig 3: Identifying Center Airbag Sensor

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
3. Turn the ignition switch to ON, and wait for at least 60 seconds.
4. Clear the DTCs. Refer to DTC CHECK / CLEAR .
5. Turn the ignition switch off.
6. Turn the ignition switch to ON, and wait for at least 60 seconds.
7. Check for DTCs. Refer to DTC CHECK / CLEAR .

   OK

   DTC B1656/38 is not output.

   HINT: 

   Codes other than DTC B1656/38 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 → See step   5 

OK → See step   7 

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

   HINT: 

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

NEXT: Go to next step 

1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
   Fig 4: Identifying Center Airbag Sensor

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Turn the ignition switch to ON, and wait for at least 60 seconds.
3. Clear the DTCs. Refer to DTC CHECK / CLEAR .
4. Turn the ignition switch off.
5. Turn the ignition switch to ON, and wait for at least 60 seconds.
6. Check for DTCs. Refer to DTC CHECK / CLEAR .

   OK

   DTC B1656/38 is not output.

   HINT: 

   Codes other than DTC B1656/38 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 → See step   8 

OK → See step   9