DTC B1771: Passenger Side Buckle Switch Circuit Malfunction: Procedure

1. Turn the ignition switch to ON.
2. Clear the DTCs. Refer to DTC CHECK / CLEAR .

   HINT: 

   First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

3. Turn the ignition switch off.
4. Turn the ignition switch to ON.
5. Check the DTCs. Refer to DTC CHECK / CLEAR .

   OK

   DTC B1771 is not output.

   HINT: 

   DTCs other than DTC B1771 may be output at this time, but they are not related to this check.

OK → USE SIMULATION METHOD TO CHECK 

NG: Go to next step 

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 occupant classification ECU and the front seat inner belt RH.

   OK

   The connectors are properly connected.

NG → CONNECT CONNECTOR 

OK: Go to next step 

1. Disconnect the connectors from the occupant classification ECU and the front seat inner belt RH.
   Fig 1: Checking Floor Wire No. 2 (To B+)

   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.
4. Measure the voltage of the wire harness side connector.

   Standard voltage

   Tester Connection	Specified Condition
   L1-9 (BSW) - Body ground	Below 1 V
   L1-5 (BGND) - Body ground	Below 1 V

NG → REPAIR OR REPLACE FLOOR WIRE NO. 2 

OK: Go to next step 

1. Turn the ignition switch off.
   Fig 2: Checking Floor Wire No. 2 (For Open)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
3. Using a service wire, connect terminals L2-3 and L2-4 of connector C.
   NOTE:

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

4. Measure the resistance of the wire harness side connectors.

   Standard resistance

   Tester Connection	Specified Condition
   L1-9 (BSW) - L1-5 (BGND)	Below 1 Ω

NG → REPAIR OR REPLACE FLOOR WIRE NO. 2 

OK: Go to next step 

1. Disconnect the service wire from connector C.
   Fig 3: Checking Floor Wire No. 2 (For Short)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance of the wire harness side connector.

   Standard resistance

   Tester Connection	Specified Condition
   L1-9 (BSW) - L1-5 (BGND)	1 MΩ or higher

NG → REPAIR OR REPLACE FLOOR WIRE NO. 2 

OK: Go to next step 

1. Measure the resistance of the wire harness side connector.
   Fig 4: Checking Floor Wire No. 2 (To Ground)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard resistance

   Tester Connection	Specified Condition
   L1-9 (BSW) - Body ground	1 MΩ or higher
   L1-5 (BGND) - Body ground	1 MΩ or higher

NG → REPAIR OR REPLACE FLOOR WIRE NO. 2 

OK: Go to next step 

1. Connect the connectors to the occupant classification ECU and the front seat inner belt RH.
2. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
3. Turn the ignition switch to ON.
4. Clear the DTCs. Refer to DTC CHECK / CLEAR .

   HINT: 

   First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

5. Turn the ignition switch off.
6. Turn the ignition switch to ON.
7. Check the DTCs. Refer to DTC CHECK / CLEAR .

   OK

   DTC B1771 is not output.

   HINT: 

   DTCs other than DTC B1771 may be output at this time, but they are not related to this check.

OK → USE SIMULATION METHOD TO CHECK 

NG: Go to next step 

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 RH. Refer to FRONT SEAT INNER BELT ASSEMBLY .

   HINT: 

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

4. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
5. Turn the ignition switch to ON.
6. Clear the DTCs. Refer to DTC CHECK / CLEAR .

   HINT: 

   First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

7. Turn the ignition switch off.
8. Turn the ignition switch to ON.
9. Check the DTCs. Refer to DTC CHECK / CLEAR .

   OK

   DTC B1771 is not output.

   HINT: 

   DTCs other than DTC B1771 may be output at this time, but they are not related to this check.

OK → END 

NG: Go to next step 

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 occupant classification ECU. Refer to OCCUPANT CLASSIFICATION ECU .

NEXT: Go to next step 

1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
2. Connect the Techstream to the DLC3.
3. Turn the ignition switch to ON.
4. Using the Techstream, perform the zero point calibration. Refer to INITIALIZATION .

   OK

   "Zero Point Calibration is complete." is displayed.

NEXT: Go to next step 

1. Using the Techstream, perform the sensitivity check. Refer to INITIALIZATION .

   Standard value

   27 to 33 kg (59.52 to 72.75 lb)

NEXT → END