DTC B1793: Occupant Classification Sensor Power Supply Circuit Malfunction [08/2015 - ]: Procedure

1. Turn the power switch off.
2. Disconnect the cable from the negative (-) auxiliary battery terminal.
3. Check that the connectors are properly connected to the 4 occupant classification sensors and occupant detection ECU.

   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 4 occupant classification sensors and occupant detection ECU.
5. Check that the terminals of the connectors are not damaged.

   OK

   The terminals are not deformed or damaged.

NG → REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

1. Connect the cable to the negative (-) auxiliary battery terminal.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

2. Turn the power switch on (IG).
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   W2-5 (SVC3) - Body ground	Power switch on (IG)	Below 1 V
   W2-6 (SVC4) - Body ground	Power switch on (IG)	Below 1 V
   W2-11 (SVC1) - Body ground	Power switch on (IG)	Below 1 V
   W2-12 (SVC2) - Body ground	Power switch on (IG)	Below 1 V

4. Turn the power switch off.
5. Disconnect the cable from the negative (-) auxiliary battery terminal.
   TEXT IN ILLUSTRATION
   
   

   *1	4 Occupant Classification Sensors
   *2	Occupant Detection ECU
   *3	Front Seat Wire RH
   *a	Front view of wire harness connector (to Occupant Detection ECU)

NG → REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   W2-5 (SVC3) - Body ground	Always	1 MΩ or higher
   W2-6 (SVC4) - Body ground	Always	1 MΩ or higher
   W2-11 (SVC1) - Body ground	Always	1 MΩ or higher
   W2-12 (SVC2) - Body ground	Always	1 MΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	4 Occupant Classification Sensors
   *2	Occupant Detection ECU
   *3	Front Seat Wire RH
   *a	Front view of wire harness connector (to Occupant Detection ECU)

NG → REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   W2-5 (SVC3) - W1-1 (SVC3)	Always	Below 1 Ω
   W2-6 (SVC4) - W7-1 (SVC4)	Always	Below 1 Ω
   W2-11 (SVC1) - W4-1 (SVC1)	Always	Below 1 Ω
   W2-12 (SVC2) - W6-1 (SVC2)	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	4 Occupant Classification Sensors
   *2	Occupant Detection ECU
   *3	Front Seat Wire RH
   *a	Front view of wire harness connector (to Occupant Detection ECU)
   *b	Front view of wire harness connector (to 4 Occupant Classification Sensors)
   *c	to Front Occupant Classification Sensor LH
   *d	to Rear Occupant Classification Sensor RH
   *e	to Front Occupant Classification Sensor RH
   *f	to Rear Occupant Classification Sensor LH

NG → REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   W2-5 (SVC3) - W2-6 (SVC4)	Always	1 MΩ or higher
   W2-5 (SVC3) - W2-11 (SVC1)	Always	1 MΩ or higher
   W2-5 (SVC3) - W2-12 (SVC2)	Always	1 MΩ or higher
   W2-6 (SVC4) - W2-11 (SVC1)	Always	1 MΩ or higher
   W2-6 (SVC4) - W2-12 (SVC2)	Always	1 MΩ or higher
   W2-11 (SVC1) - W2-12 (SVC2)	Always	1 MΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	4 Occupant Classification Sensors
   *2	Occupant Detection ECU
   *3	Front Seat Wire RH
   *a	Front view of wire harness connector (to Occupant Detection ECU)

NG → REPLACE FRONT SEAT WIRE RH 

OK: Go to next step 

1. Connect the connectors to the occupant detection ECU and 4 occupant classification sensors.
2. Connect the cable to the negative (-) auxiliary battery terminal.
3. Clear the DTCs stored in the occupant detection ECU. Refer to DTC CHECK / CLEAR [08/2015 - ] .
4. Clear the DTCs stored in the airbag ECU assembly. Refer to DTC CHECK / CLEAR [08/2015 - ] .
5. Turn the power switch off.
6. Turn the power switch on (IG).
7. Check for DTCs. Refer to DTC CHECK / CLEAR [08/2015 - ] .

   OK

   DTC B1793 is not output.

   HINT: 

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

8. Turn the power switch off.

NG → Refer to   7 

OK → Refer to   10 

1. Disconnect the cable from the negative (-) auxiliary battery terminal.
2. Replace the separate type front seat cushion spring assembly RH. Refer to REMOVAL [08/2015 - ] .
3. Connect the cable to the negative (-) auxiliary battery terminal.

NEXT: Go to next step 

1. Using the Techstream, perform Zero Point Calibration. Refer to INITIALIZATION [08/2015 - ] .

NEXT: Go to next step 

1. Using the Techstream, perform Sensitivity Check. Refer to INITIALIZATION [08/2015 - ] .

NEXT → END