DTC B1793: Occupant Classification Sensor Power Supply Circuit Malfunction: Procedure

1. Turn the ignition switch ON, and wait for at least 60 seconds.
2. Clear any DTCs stored in the memory. Refer to DTC CHECK / CLEAR .

   HINT: 

   • First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.
   • Use a Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
3. Turn the ignition switch off.
4. Turn the ignition switch ON, and wait for at least 60 seconds.
5. Using the Techstream, check for DTCs of the occupant classification ECU. Refer to DTC CHECK / CLEAR .

   OK

   DTC B1793 is not output.

   HINT: 

   DTCs other than DTC B1793 may be output at this time, but they are not related to this check.

NG → See step   2 

OK → See step   9 

1. Turn the ignition switch off.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Check that the connectors are properly connected to the occupant classification ECU and the occupant classification sensors.

   OK

   Connectors are properly connected.

NG → CONNECT CONNECTOR 

OK: Go to next step 

1. Check that the connectors (on the occupant classification ECU side and the occupant classification sensors side) are not damaged. Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE .

   OK

   Connectors are not deformed or damaged.

NG → REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

1. Disconnect the connectors from the occupant classification ECU and the 4 occupant classification sensors.
   Fig 1: Measuring Voltage Of Front Seat Wire RH Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
3. Turn the ignition switch ON, and wait for at least 60 seconds.
4. Measure the voltage according to the value(s) in the table below.

   Standard voltage

   Tester Connection	Switch Condition	Specified Condition
   z8-11 (SVC1) - Body ground	Ignition switch ON	Below 1 V
   z8-12 (SVC2) - Body ground
   z8-5 (SVC3) - Body ground
   z8-6 (SVC4) - Body ground

5. Turn the ignition switch off.
6. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
7. Measure the resistance according the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   z8-11 (SVC1) - z9-1 (SVC1)	Always	Blow 1 Ω
   z8-12 (SVC2) - z11-1 (SVC2)
   z8-5 (SVC3) - z10-1 (SVC3)
   z8-6 (SVC4) - z12-1 (SVC4)

   Standard resistance

   Tester Connection	Condition	Specified Condition
   z8-11 (SVC1) - Body ground	Always	1 MΩ or higher
   z8-12 (SVC2) - Body ground
   z8-5 (SVC3) - Body ground
   z8-6 (SVC4) - Body ground
   z8-11 (SVC1) - z8-12 (SVC2)
   z8-11 (SVC1) - z8-5 (SVC3)
   z8-11 (SVC1) - z8-6 (SVC4)
   z8-12 (SVC2) - z8-5 (SVC3)
   z8-12 (SVC2) - z8-6 (SVC4)
   z8-5 (SVC3) - z8-6 (SVC4)

NG → REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

1. Connect the connectors to the occupant classification ECU and the 4 occupant classification sensors.
2. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
3. Turn the ignition switch ON, and wait for at least 60 seconds.
4. Clear any DTCs stored in the memory. Refer to DTC CHECK / CLEAR .

   HINT: 

   • First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.
   • Use a Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
5. Turn the ignition switch off.
6. Turn the ignition switch ON, and wait for at least 60 seconds.
7. Using the Techstream, check for DTCs of the occupant classification ECU. Refer to DTC CHECK / CLEAR .

   OK

   DTC B1793 is not output.

   HINT: 

   DTCs other than DTC B1793 may be output at this time, but they are not related to this check.

NG → See step   6 

OK → See step   9 

1. Turn the ignition switch off.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Replace the occupant classification ECU. Refer to REMOVAL .

   HINT: 

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

NEXT: Go to next step 

1. Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
2. Connect a Techstream to the DLC3.
3. Turn the ignition switch ON, and wait for at least 60 seconds.
4. Using the Techstream, perform the zero point calibration. Refer to INITIALIZATION .

NEXT: Go to next step 

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

   Standard range

   27 to 33 kg (59.5 to 72.8 lb)

NEXT → END