DTC B1783: Rear Occupant Classification Sensor RH 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 B1783 is not output.

   HINT: 

   DTCs other than DTC B1783 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 rear occupant classification sensor 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 rear occupant classification sensor RH.
   Fig 1: Checking Front Seat Wire RH (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
   a1-4 (SGD4) - Body ground	Below 1 V
   a1-6 (SVC4) - Body ground	Below 1 V
   a1-10 (SIG4) - Body ground	Below 1 V

NG → REPAIR OR REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

1. Turn the ignition switch off.
   Fig 2: Checking Front Seat Wire RH (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 a5-1 (SVC4) and a5-3 (SGD4), and connect terminals a5-2 (SIG4) and a5-3 (SGD4) 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 connector.

   Standard resistance 

   Tester Connection	Specified Condition
   a1-6 (SVC4) - a1-4 (SGD4)	Below 1 Ω
   a1-10 (SIG4) - a1-4 (SGD4)	Below 1 Ω

NG → REPAIR OR REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

1. Disconnect the service wire from connector C.
   Fig 3: Checking Front Seat Wire RH (For Short)

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

   Standard resistance 

   Tester Connection	Specified Condition
   a1-6 (SVC4) - a1-4 (SGD4)	1 MΩ or higher
   a1-10 (SIG4) - a1-4 (SGD4)	1 MΩ or higher
   a1-6 (SVC4) - a1-10 (SIG4)	1 MΩ or higher

NG → REPAIR OR REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

1. Measure the resistance of the wire harness side connector.
   Fig 4: Checking Front Seat Wire RH (To Ground)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard resistance 

   Tester Connection	Specified Condition
   a1-4 (SGD4) - Body ground	1 MΩ or higher
   a1-6 (SVC4) - Body ground	1 MΩ or higher
   a1-10 (SIG4) - Body ground	1 MΩ or higher

NG → REPAIR OR REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

1. Connect the connectors to the occupant classification ECU and the rear occupant classification sensor 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 B1783 is not output.

   HINT: 

   DTCs other than DTC B1783 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 occupant classification ECU.Refer to COMPONENTS .

   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.
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.

NG → See step   12 

OK: 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)

NG → See step   12 

OK: Go to next step 

1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
2. Turn the ignition switch to ON.
3. 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.

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

   OK

   DTC B1783 is not output.

   HINT: 

   DTCs other than DTC B1783 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 front seat with adjuster frame assembly RH.Refer to COMPONENTS .

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