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.
   WARNING:

   Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

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

   OK

   The connectors are properly connected.

   HINT: 

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

4. Disconnect the connectors from the airbag sensor assembly and front seat inner belt assembly LH.
5. Check that the terminals of the connectors are not damaged.

   OK

   The terminals are not deformed or damaged.

NG → REPLACE FLOOR WIRE 

OK: Go to next step 

1. Using a service wire, connect terminals 10 (LBE+) and 18 (LBE-) of connector B.
   Fig 1: Checking Floor Wire

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   NOTE:

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

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   N32-2 (LBE+) - N32-1 (LBE-)	Always	Below 1 Ω

3. Disconnect the service wire from connector B.
   TEXT IN ILLUSTRATION
   
   

   *1	Front Seat Inner Belt Assembly LH
   *2	Airbag Sensor Assembly
   *3	Floor Wire
   *4	Service Wire
   *a	Front view of wire harness connector (to Airbag Sensor Assembly)
   *b	Front view of wire harness connector (to Front Seat Inner Belt Assembly LH)

NG → REPLACE FLOOR WIRE 

OK: Go to next step 

Fig 2: Checking Floor Wire

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   N32-2 (LBE+) - N32-1 (LBE-)	Always	1 MΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Front Seat Inner Belt Assembly LH
   *2	Airbag Sensor Assembly
   *3	Floor Wire
   *a	Front view of wire harness connector (to Front Seat Inner Belt Assembly LH)

NG → REPLACE FLOOR WIRE 

OK: Go to next step 

1. Connect the cable to the negative (-) battery terminal.
   Fig 3: Checking Floor Wire

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Turn the ignition switch to ON.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   N32-2 (LBE+) - Body ground	Ignition switch ON	Below 1 V
   N32-1 (LBE-) - Body ground	Ignition switch ON	Below 1 V

4. Turn the ignition switch off.
5. Disconnect the cable from the negative (-) battery terminal.
   WARNING:

   Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

   TEXT IN ILLUSTRATION
   
   

   *1	Front Seat Inner Belt Assembly LH
   *2	Airbag Sensor Assembly
   *3	Floor Wire
   *a	Front view of wire harness connector (to Front Seat Inner Belt Assembly LH)

NG → REPLACE FLOOR WIRE 

OK: Go to next step 

1. Measure the resistance according to the value(s) in the table below.
   Fig 4: Checking Floor Wire

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   N32-2 (LBE+) - Body ground	Always	1 MΩ or higher
   N32-1 (LBE-) - Body ground	Always	1 MΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Front Seat Inner Belt Assembly LH
   *2	Airbag Sensor Assembly
   *3	Floor Wire
   *a	Front view of wire harness connector (to Front Seat Inner Belt Assembly LH)

NG → REPLACE FLOOR WIRE 

OK: Go to next step 

1. Connect the connectors to the airbag sensor assembly and front seat inner belt assembly LH.
   Fig 5: Checking Side Airbag Sensor Assembly

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Connect the cable to the negative (-) battery terminal.
3. Clear the DTCs stored in memory. 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 Assembly LH
   *2	Airbag Sensor Assembly

NG → See step   7 

OK → See step   8 

1. Turn the ignition switch off.
   Fig 6: Checking Side Airbag Sensor Assembly

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the cable from the negative (-) battery terminal.
   WARNING:

   Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

3. Replace the front seat inner belt assembly LH with a known good one. Refer to REMOVAL for Manual Seat. Refer to REMOVAL for Power Seat).

   HINT: 

   Perform the following inspection using known good parts from another vehicle if possible.

4. Connect the cable to the negative (-) battery terminal.
5. Clear the DTCs stored in memory. Refer to DTC CHECK / CLEAR .
6. Turn the ignition switch off.
7. Turn the ignition switch to ON, and wait for at least 60 seconds.
8. Check for DTCs. Refer to DTC CHECK / CLEAR .

   OK

   DTC B1656/38 is not output.

   RESULT
   
   

   Result	Proceed to
   OK (for Manual Seat)	A
   OK (for Power Seat)	B
   NG	C

   HINT: 

   Codes other than DTC B1656/38 may be output at this time, but they are not related to this check.

9. Turn the ignition switch off.
10. Disconnect the cable from the negative (-) battery terminal.
11. Restore the front seat inner belt assembly LH that was installed for testing to its original location. Refer to REMOVAL for Manual Seat. Refer to REMOVAL for Power Seat).
    TEXT IN ILLUSTRATION
    
    

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

B → See step   11 

C → See step   9 

A → See step   10