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Occupant Classification System (diagnostic Codes & Symptom Tests) Toyota Prius C I

Airbag 18 illustrations ~8897 words

DESCRIPTION

The passenger side buckle switch circuit consists of the occupant detection ECU and front seat inner belt assembly RH.

DTC B1771 is stored when a malfunction is detected in the passenger side buckle switch circuit.

DTC No.DTC Detection ConditionTrouble Area
B1771The occupant detection ECU receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the passenger side buckle switch circuit. Passenger side buckle switch malfunction Occupant detection ECU malfunctionFront seat wire RH Front seat inner belt assembly RH (Passenger side buckle switch) Occupant detection ECU

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1771 is output, perform troubleshooting for the DTC.

Scheme 172

Scheme 172: WIRING DIAGRAM
Scheme 172: WIRING DIAGRAM

INSPECTION PROCEDURE

Note. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work. Refer to PRECAUTION .

HINT

  1. If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to see under the seat cushion.
  2. In the above case, lift and hold the seat so that it does not fall down. Hold the seat only as necessary because holding the seat for a long period of time may cause seat rail deformation.

Scheme 173

Scheme 173: PROCEDURE
Scheme 173: PROCEDURE

Scheme 174

Scheme 174
Scheme 174
  1. CHECK CONNECTORS Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Check that the connectors are properly connected to the occupant detection ECU and front seat inner belt assembly RH. OK The connectors are properly connected. HINT: If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection. Disconnect the connectors from the occupant detection ECU and front seat inner belt assembly RH. 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
  2. CHECK FRONT SEAT WIRE RH (SHORT TO B+) Connect the cable to the negative (-) auxiliary battery terminal. Turn the ignition switch to ON (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition Y3-8 (BSW) - Body ground Ignition switch ON (IG) Below 1 V Y3-5 (BGND) - Body ground Ignition switch ON (IG) Below 1 V Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. TEXT IN ILLUSTRATION *1 Front Seat Inner Belt Assembly RH *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
  3. CHECK FRONT SEAT WIRE RH (OPEN) Using a service wire, connect terminals BSW and BGND of connector C as shown in the illustration. NOTE: Do not forcibly insert the service wire into the terminals of the connector when connecting the wire. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y3-8 (BSW) - Y3-5 (BGND) Always Below 1 ohms Disconnect the service wire from connector C. TEXT IN ILLUSTRATION *1 Front Seat Inner Belt Assembly RH *2 Occupant Detection ECU *3 Front Seat Wire RH *4 Service Wire *a Front view of wire harness connector (to Occupant Detection ECU) *b Front view of wire harness connector (to Front Seat Inner Belt Assembly RH) NG --> REPLACE FRONT SEAT WIRE RH OK: Go to next step
  4. CHECK FRONT SEAT WIRE RH (SHORT) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y3-8 (BSW) - Y3-5 (BGND) Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Front Seat Inner Belt Assembly RH *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
  5. CHECK FRONT SEAT WIRE RH (SHORT TO GROUND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y3-8 (BSW) - Body ground Always 1 Mohms or higher Y3-5 (BGND) - Body ground Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Front Seat Inner Belt Assembly RH *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
  6. CHECK DTC Connect the connectors to the occupant detection ECU and front seat inner belt assembly RH. Connect the cable to the negative (-) auxiliary battery terminal. Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1771 is not output. HINT: Codes other than DTC B1771 may be output at this time, but they are not related to this check. Turn the ignition switch off. NG --> See step 7 OK --> See step 10
  7. CHECK FRONT SEAT INNER BELT ASSEMBLY RH Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the front seat inner belt assembly RH with a known good one. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/restraints-control-systems/#seat-belt-service-information) . HINT: Perform the following inspection using known good parts from another vehicle if possible. Connect the cable to the negative (-) auxiliary battery terminal. Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1771 is not output. HINT: Codes other than DTC B1771 may be output at this time, but they are not related to this check. Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Return the front seat inner belt assembly RH that was installed for testing to its original location. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/restraints-control-systems/#seat-belt-service-information) . NG --> See step 8 OK --> See step 11
  8. REPLACE OCCUPANT DETECTION ECU Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU with a new one. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  9. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  10. USE SIMULATION METHOD TO CHECK. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(/toyota/prius-c/i-2011-2015/remont/hoistjack/#introduction)
  11. REPLACE FRONT SEAT INNER BELT ASSEMBLY RH. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/restraints-control-systems/#seat-belt-service-information)

The rear occupant classification sensor LH circuit consists of the occupant detection ECU and rear occupant classification sensor LH.

DTC B1782 is stored when a malfunction is detected in the rear occupant classification sensor LH circuit.

DTC No.DTC Detection ConditionTrouble Area
B1782The occupant detection ECU receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the rear occupant classification sensor LH circuit. Rear occupant classification sensor LH malfunction Occupant detection ECU malfunctionFront seat wire RH Separate type front seat cushion spring assembly (Rear occupant classification sensor LH) Occupant detection ECU

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1782 is output, perform troubleshooting for the DTC.

Scheme 175

Scheme 175: WIRING DIAGRAM
Scheme 175: WIRING DIAGRAM

Note. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work. Refer to PRECAUTION .

HINT

  1. If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to see under the seat cushion.
  2. In the above case, lift and hold the seat so that it does not fall down. Hold the seat only as necessary because holding the seat for a long period of time may cause seat rail deformation.

Scheme 176

Scheme 176: PROCEDURE
Scheme 176: PROCEDURE

Scheme 177

Scheme 177
Scheme 177
  1. CHECK CONNECTORS Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Check that the connectors are properly connected to the occupant detection ECU and rear occupant classification sensor LH. OK The connectors are properly connected. HINT: If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection. Disconnect the connectors from the occupant detection ECU and rear occupant classification sensor LH. 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
  2. CHECK FRONT SEAT WIRE RH (SHORT TO B+) Connect the cable to the negative (-) auxiliary battery terminal. Turn the ignition switch to ON (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition Y2-1 (SVC3) - Body ground Ignition switch ON (IG) Below 1 V Y2-3 (SIG3) - Body ground Ignition switch ON (IG) Below 1 V Y2-5 (SGD3) - Body ground Ignition switch ON (IG) Below 1 V Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. TEXT IN ILLUSTRATION *1 Rear Occupant Classification Sensor LH *2 Occupant Detection ECU *3 Front Seat Wire RH *a Front view of wire harness connector (to Occupant Detection ECU) NG --> See step 12 OK: Go to next step
  3. CHECK FRONT SEAT WIRE RH (OPEN) Using a service wire, connect terminals 1 (SVC3) and 3 (SGD3), and connect terminals 2 (SIG3) and 3 (SGD3) of connector C. NOTE: Do not forcibly insert the service wire into the terminals of the connector when connecting the wire. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y2-1 (SVC3) - Y2-5 (SGD3) Always Below 1 ohms Y2-3 (SIG3) - Y2-5 (SGD3) Always Below 1 ohms Disconnect the service wire from connector C. TEXT IN ILLUSTRATION *1 Rear Occupant Classification Sensor LH *2 Occupant Detection ECU *3 Front Seat Wire RH *4 Service Wire *a Front view of wire harness connector (to Occupant Detection ECU) *b Front view of wire harness connector (to Rear Occupant Classification Sensor LH) NG --> REPLACE FRONT SEAT WIRE RH OK: Go to next step
  4. CHECK FRONT SEAT WIRE RH (SHORT) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y2-1 (SVC3) - Y2-5 (SGD3) Always 1 Mohms or higher Y2-3 (SIG3) - Y2-5 (SGD3) Always 1 Mohms or higher Y2-1 (SVC3) - Y2-3 (SIG3) Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Rear Occupant Classification Sensor LH *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
  5. CHECK FRONT SEAT WIRE RH (SHORT TO GROUND) Measure the resistance according to value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y2-1 (SVC3) - Body ground Always 1 Mohms or higher Y2-3 (SIG3) - Body ground Always 1 Mohms or higher Y2-5 (SGD3) - Body ground Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Rear Occupant Classification Sensor LH *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
  6. CHECK DTC Connect the connectors to the occupant detection ECU and rear occupant classification sensor LH. Connect the cable to the negative (-) auxiliary battery terminal. Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1782 is not output. HINT: Codes other than DTC B1782 may be output at this time, but they are not related to this check. Turn the ignition switch off. NG --> See step 7 OK --> See step 14
  7. CHECK OCCUPANT DETECTION ECU Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU with a known good one. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . HINT: Perform the following inspection using known good parts from another vehicle if possible. Connect the cable to the negative (-) auxiliary battery terminal. Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1782 is not output. HINT: Codes other than DTC B1782 may be output at this time, but they are not related to this check. Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Return the occupant detection ECU that was installed for testing to its original location. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . NG --> See step 10 OK: Go to next step
  8. REPLACE OCCUPANT DETECTION ECU Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU with a new one. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  9. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  10. REPLACE SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the separate type front seat cushion spring assembly. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Non-removable Headrest. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Removable Headrest). Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  11. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  12. REPLACE SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the separate type front seat cushion spring assembly. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Non-removable Headrest. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Removable Headrest). NOTE: Replace the front seat wire RH at the same time. HINT: When the front seat wire RH has a short to B+, the rear occupant classification sensor LH will be damaged. Therefore, replace the front seat wire RH and the separate type front seat cushion spring assembly, which includes the rear occupant classification sensor LH. Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  13. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  14. USE SIMULATION METHOD TO CHECK. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(/toyota/prius-c/i-2011-2015/remont/hoistjack/#introduction)

The rear occupant classification sensor RH circuit consists of the occupant detection ECU and rear occupant classification sensor RH.

DTC B1783 is stored when a malfunction is detected in the rear occupant classification sensor RH circuit.

DTC No.DTC Detecting ConditionTrouble Area
B1783The occupant detection ECU receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the rear occupant classification sensor RH circuit. Rear occupant classification sensor RH malfunction Occupant detection ECU malfunctionFront seat wire RH Separate type front seat cushion spring assembly (Rear occupant classification sensor RH) Occupant detection ECU

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1783 is output, perform troubleshooting for the DTC.

Scheme 178

Scheme 178: WIRING DIAGRAM
Scheme 178: WIRING DIAGRAM

Note. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work. Refer to PRECAUTION .

HINT

  1. If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to see under the seat cushion.
  2. In the above case, lift and hold the seat so that it does not fall down. Hold the seat only as necessary because holding the seat for a long period of time may cause seat rail deformation.

Scheme 179

Scheme 179: PROCEDURE
Scheme 179: PROCEDURE

Scheme 180

Scheme 180
Scheme 180
  1. CHECK CONNECTORS Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Check that the connectors are properly connected to the occupant detection ECU and rear occupant classification sensor RH. OK The connectors are properly connected. HINT: If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection. Disconnect the connectors from the occupant detection ECU and rear occupant classification sensor RH. 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
  2. CHECK FRONT SEAT WIRE RH (SHORT TO B+) Connect the cable to the negative (-) auxiliary battery terminal. Turn the ignition switch to ON (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition Y2-2 (SVC4) - Body ground Ignition switch ON (IG) Below 1 V Y2-4 (SIG4) - Body ground Ignition switch ON (IG Below 1 V Y2-6 (SGD4) - Body ground Ignition switch ON (IG Below 1 V Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. TEXT IN ILLUSTRATION *1 Rear Occupant Classification Sensor RH *2 Occupant Detection ECU *3 Front Seat Wire RH *a Front view of wire harness connector (to Occupant Detection ECU) NG --> See step 12 OK: Go to next step
  3. CHECK FRONT SEAT WIRE RH (OPEN) Using a service wire, connect terminals 1 (SVC4) and 3 (SGD4), and connect terminals 2 (SIG4) and 3 (SGD4) of connector C. NOTE: Do not forcibly insert the service wire into the terminals of the connector when connecting the wire. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y2-2 (SVC4) - Y2-6 (SGD4) Always Below 1 ohms Y2-4 (SIG4) - Y2-6 (SGD4) Always Below 1 ohms Disconnect the service wire from connector C. TEXT IN ILLUSTRATION *1 Rear Occupant Classification Sensor RH *2 Occupant Detection ECU *3 Front Seat Wire RH *4 Service Wire *a Front view of wire harness connector (to Occupant Detection ECU) *b Front view of wire harness connector (to Rear Occupant Classification Sensor RH) NG --> REPLACE FRONT SEAT WIRE RH OK: Go to next step
  4. CHECK FRONT SEAT WIRE RH (SHORT) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y2-2 (SVC4) - Y2-6 (SGD4) Always 1 Mohms or higher Y2-4 (SIG4) - Y2-6 (SGD4) Always 1 Mohms or higher Y2-2 (SVC4) - Y2-4 (SIG4) Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Rear Occupant Classification Sensor RH *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
  5. CHECK FRONT SEAT WIRE RH (SHORT TO GROUND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y2-2 (SVC4) - Body ground Always 1 Mohms or higher Y2-4 (SIG4) - Body ground Always 1 Mohms or higher Y2-6 (SGD4) - Body ground Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Rear Occupant Classification Sensor RH *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
  6. CHECK DTC Connect the connectors to the occupant detection ECU and rear occupant classification sensor RH. Connect the cable to the negative (-) auxiliary battery terminal. Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1783 is not output. HINT: Codes other than DTC B1783 may be output at this time, but they are not related to this check. Turn the ignition switch off. NG --> See step 7 OK --> See step 14
  7. CHECK OCCUPANT DETECTION ECU Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU with a known good one. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . HINT: Perform the following inspection using known good parts from another vehicle if possible. Connect the cable to the negative (-) auxiliary battery terminal. Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1783 is not output. HINT: Codes other than DTC B1783 may be output at this time, but they are not related to this check. Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Return the occupant detection ECU that was installed for testing to its original location. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . NG --> See step 10 OK: Go to next step
  8. REPLACE OCCUPANT DETECTION ECU Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU with a new one. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  9. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  10. REPLACE SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the separate type front seat cushion spring assembly. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Non-removable Headrest. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Removable Headrest). Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  11. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  12. REPLACE SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the separate type front seat cushion spring assembly. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Non-removable Headrest. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Removable Headrest). NOTE: Replace the front seat wire RH at the same time. HINT: When the front seat wire RH has a short to B+, the rear occupant classification sensor RH will be damaged. Therefore, replace the front seat wire RH and the separate type front seat cushion spring assembly, which includes the rear occupant classification sensor RH. Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  13. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  14. USE SIMULATION METHOD TO CHECK. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(/toyota/prius-c/i-2011-2015/remont/hoistjack/#introduction)

DTC B1787 is stored when the occupant detection ECU receives a collision detection signal sent by the rear occupant classification sensor LH if an accident occurs.

DTC B1787 is also stored when the front seat assembly RH is subjected to a strong impact, even if an actual accident does not occur.

If the vehicle was not in a collision, but the occupant detection ECU receives a collision detection signal and stores DTC B1787, the DTC can be cleared by performing Zero Point Calibration and Sensitivity Check.

Therefore, if DTC B1787 is output, first perform Zero Point Calibration and Sensitivity Check.

DTC No.DTC Detection ConditionTrouble Area
B1787Rear occupant classification sensor LH sensed large load Separate type front seat cushion spring assembly malfunctionSeparate type front seat cushion spring assembly (Rear occupant classification sensor LH)

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1787 is output, perform troubleshooting for the DTC.

WIRING DIAGRAM

Refer to DTC B1782. Refer to WIRING DIAGRAM .

Note. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work. Refer to PRECAUTION .

PROCEDURE

  1. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . OK "Zero Point Calibration is complete." and "Sensitivity Check is complete." are displayed. NG --> See step 3 OK: Go to next step
  2. CHECK DTC Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1787 is not output. HINT: Codes other than DTC B1787 may be output at this time, but they are not related to this check. Turn the ignition switch off. NG --> See step 3 OK --> END
  3. REPLACE SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the separate type front seat cushion spring assembly. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Non-removable Headrest. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Removable Headrest). Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  4. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END

DTC B1788 is stored when the occupant detection ECU receives a collision detection signal sent by the rear occupant classification sensor RH if an accident occurs.

DTC B1788 is also stored when the front seat assembly RH is subjected to a strong impact, even if an actual accident does not occur.

If the vehicle was not in a collision, but the occupant detection ECU receives a collision detection signal and stores DTC B1788, the DTC can be cleared by performing the Zero Point Calibration and Sensitivity Check.

Therefore, if DTC B1788 is output, first perform Zero Point Calibration and Sensitivity Check.

DTC No.DTC Detection ConditionTrouble Area
B1788Rear occupant classification sensor RH sensed large load Separate type front seat cushion spring assembly malfunctionSeparate type front seat cushion spring assembly (Rear occupant classification sensor RH)

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1788 is output, perform troubleshooting for the DTC.

Refer to DTC B1783. Refer to WIRING DIAGRAM .

Note. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work. Refer to PRECAUTION .

  1. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . OK "Zero Point Calibration is complete." and "Sensitivity Check is complete." are displayed. NG --> See step 3 OK: Go to next step
  2. CHECK DTC Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1788 is not output. HINT: Codes other than DTC B1788 may be output at this time, but they are not related to this check. Turn the ignition switch off. NG --> See step 3 OK --> END
  3. REPLACE SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the separate type front seat cushion spring assembly. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Non-removable Headrest. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Removable Headrest). Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  4. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END

The airbag sensor assembly communication circuit consists of the occupant detection ECU and airbag sensor assembly.

DTC B1790 is stored when a malfunction is detected in the airbag sensor assembly communication circuit.

DTC No.DTC Detection ConditionTrouble Area
B1790The occupant detection ECU receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the airbag sensor assembly communication circuit. Occupant detection ECU malfunction Airbag sensor assembly malfunctionFloor wire Front seat wire RH Occupant detection ECU Airbag sensor assembly

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1790 is output, perform troubleshooting for the DTC.

Scheme 181

Scheme 181: WIRING DIAGRAM
Scheme 181: WIRING DIAGRAM

Note. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work. Refer to PRECAUTION .

HINT

  1. If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to see under the seat cushion.
  2. In the above case, lift and hold the seat so that it does not fall down. Hold the seat only as necessary because holding the seat for a long period of time may cause seat rail deformation.

Scheme 182

Scheme 182: PROCEDURE
Scheme 182: PROCEDURE

Scheme 183

Scheme 183
Scheme 183

Scheme 184

Scheme 184
Scheme 184

Scheme 185

Scheme 185
Scheme 185
  1. CHECK CONNECTORS Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. WARNING: Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system. Check that the connectors are properly connected to the airbag sensor assembly and occupant detection ECU. Also check that the connectors that link the front seat wire RH and floor wire are properly connected. OK The connectors are properly connected. HINT: If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection. Disconnect the connectors from the airbag sensor assembly and occupant detection ECU. Also disconnect the connectors that link the front seat wire RH and floor wire. Check that the terminals of the connectors are not damaged. OK The terminals are not deformed or damaged. NG --> REPLACE WIRE HARNESS OK: Go to next step
  2. CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (SHORT TO B+) Connect the connectors that link the floor wire and front seat wire RH. Connect the cable to the negative (-) auxiliary battery terminal. Turn the ignition switch to ON (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition Y3-7 (FSR+) - Body ground Ignition switch ON (IG) Below 1 V Y3-4 (FSR-) - Body ground Ignition switch ON (IG) Below 1 V Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. WARNING: Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system. TEXT IN ILLUSTRATION *1 Occupant Detection ECU *2 Airbag Sensor Assembly *a Front view of wire harness connector (to Occupant Detection ECU) NG --> See step 10 OK: Go to next step
  3. CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (OPEN) Using a service wire, connect terminals 12 (FSR+) and 13 (FSR-) of connector B. NOTE: Do not forcibly insert the service wire into the terminals of the connector when connecting the wire. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y3-7 (FSR+) - Y3-4 (FSR-) Always Below 1 ohms TEXT IN ILLUSTRATION *1 Occupant Detection ECU *2 Airbag Sensor Assembly *3 Service Wire *a Front view of wire harness connector (to Airbag Sensor Assembly) *b Front view of wire harness connector (to Occupant Detection ECU) NG --> See step 11 OK: Go to next step
  4. CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (SHORT) Disconnect the service wire from connector B. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y3-7 (FSR+) - Y3-4 (FSR-) Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Occupant Detection ECU *2 Airbag Sensor Assembly *a Front view of wire harness connector (to Occupant Detection ECU) NG --> See step 12 OK: Go to next step
  5. CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (SHORT TO GROUND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y3-7 (FSR+) - Body ground Always 1 Mohms or higher Y3-4 (FSR-) - Body ground Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Occupant Detection ECU *2 Airbag Sensor Assembly *a Front view of wire harness connector (to Occupant Detection ECU) NG --> See step 13 OK: Go to next step
  6. CHECK DTC Connect the connectors to the occupant detection ECU and airbag sensor assembly. Connect the cable to the negative (-) auxiliary battery terminal. Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1790 is not output. HINT: Codes other than DTC B1790 may be output at this time, but they are not related to this check. Turn the ignition switch off. NG --> See step 7 OK --> See step 14
  7. CHECK OCCUPANT DETECTION ECU Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU with a known good one. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . HINT: Perform the following inspection using known good parts from another vehicle if possible. Connect the cable to the negative (-) auxiliary battery terminal. Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1790 is not output. HINT: Codes other than DTC B1790 may be output at this time, but they are not related to this check. Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Return the occupant detection ECU that was installed for testing to its original location. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . NG --> See step 15 OK: Go to next step
  8. REPLACE OCCUPANT DETECTION ECU Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU with a new one. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  9. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  10. CHECK FLOOR WIRE (SHORT TO B+) Disconnect the front seat wire RH connector from the floor wire. Connect the cable to the negative (-) auxiliary battery terminal. Turn the ignition switch to ON (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition MY1-1 (FSR+) - Body ground Ignition switch ON (IG) Below 1 V MY1-5 (FSR-) - Body ground Ignition switch ON (IG) Below 1 V TEXT IN ILLUSTRATION *1 Occupant Detection ECU *2 Airbag Sensor Assembly *3 Front Seat Wire RH *4 Floor Wire *a Front view of wire harness connector (to Front Seat Wire RH) NG --> REPLACE FLOOR WIRE OK --> REPLACE FRONT SEAT WIRE RH
  11. CHECK FLOOR WIRE (OPEN) Disconnect the front seat wire RH connector from the floor wire. HINT: The service wire has already been inserted into connector B. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition MY1-1 (FSR+) - MY1-5 (FSR-) Always Below 1 ohms Disconnect the service wire from connector B. TEXT IN ILLUSTRATION *1 Occupant Detection ECU *2 Airbag Sensor Assembly *3 Front Seat Wire RH *4 Floor Wire *5 Service Wire *a Front view of wire harness connector (to Airbag Sensor Assembly) *b Front view of wire harness connector (to Front Seat Wire RH) NG --> REPLACE FLOOR WIRE OK --> REPLACE FRONT SEAT WIRE RH
  12. CHECK FLOOR WIRE (SHORT) Disconnect the front seat wire RH connector from the floor wire. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition MY1-1 (FSR+) - MY1-5 (FSR-) Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Occupant Detection ECU *2 Airbag Sensor Assembly *3 Front Seat Wire RH *4 Floor Wire *a Front view of wire harness connector (to Front Seat Wire RH) NG --> REPLACE FLOOR WIRE OK --> REPLACE FRONT SEAT WIRE RH
  13. CHECK FLOOR WIRE (SHORT TO GROUND) Disconnect the front seat wire RH connector from the floor wire. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition MY1-1 (FSR+) - Body ground Always 1 Mohms or higher MY1-5 (FSR-) - Body ground Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Occupant Detection ECU *2 Airbag Sensor Assembly *3 Front Seat Wire RH *4 Floor Wire *a Front view of wire harness connector (to Front Seat Wire RH) NG --> REPLACE FLOOR WIRE OK --> REPLACE FRONT SEAT WIRE RH
  14. USE SIMULATION METHOD TO CHECK. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(/toyota/prius-c/i-2011-2015/remont/hoistjack/#introduction)
  15. REPLACE AIRBAG SENSOR ASSEMBLY. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information)

The occupant classification sensor power supply circuit consists of the occupant detection ECU and rear occupant classification sensors.

DTC B1793 is stored when a malfunction is detected in the occupant classification sensor power supply circuit.

DTC No.DTC Detection ConditionTrouble Area
B1793The occupant detection ECU receives a line short circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the occupant classification sensor power supply circuit. Rear occupant classification sensor LH malfunction Rear occupant classification sensor RH malfunction Occupant detection ECU malfunctionFront seat wire RH Separate type front seat cushion spring assembly (2 rear occupant classification sensors) Occupant detection ECU

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1793 is output, perform troubleshooting for the DTC.

Scheme 186

Scheme 186: WIRING DIAGRAM
Scheme 186: WIRING DIAGRAM

Note. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work. Refer to PRECAUTION .

HINT

  1. If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to see under the seat cushion.
  2. In the above case, lift and hold the seat so that it does not fall down. Hold the seat only as necessary because holding the seat for a long period of time may cause seat rail deformation.

Scheme 187

Scheme 187: PROCEDURE
Scheme 187: PROCEDURE
  1. CHECK CONNECTORS Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Check that the connectors are properly connected to the 2 rear 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. Disconnect the connectors from the 2 rear occupant classification sensors and occupant detection ECU. 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
  2. CHECK FRONT SEAT WIRE RH (SHORT TO B+) Connect the cable to the negative (-) auxiliary battery terminal. Turn the ignition switch to ON (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition Y2-1 (SVC3) - Body ground Ignition switch ON (IG) Below 1 V Y2-2 (SVC4) - Body ground Ignition switch ON (IG) Below 1 V Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. TEXT IN ILLUSTRATION *1 Rear Occupant Classification Sensor LH *2 Rear Occupant Classification Sensor RH *3 Occupant Detection ECU *4 Front Seat Wire RH *a Front view of wire harness connector (to Occupant Detection ECU) NG --> See step 11 OK: Go to next step
  3. CHECK FRONT SEAT WIRE RH (SHORT TO GROUND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y2-1 (SVC3) - Body ground Always 1 Mohms or higher Y2-2 (SVC4) - Body ground Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Rear Occupant Classification Sensor LH *2 Rear Occupant Classification Sensor RH *3 Occupant Detection ECU *4 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
  4. CHECK FRONT SEAT WIRE RH (SHORT) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y2-1 (SVC3) - Y2-2 (SVC4) Always 1 Mohms or higher TEXT IN ILLUSTRATION *1 Rear Occupant Classification Sensor LH *2 Rear Occupant Classification Sensor RH *3 Occupant Detection ECU *4 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
  5. CHECK DTC Connect the connectors to the occupant detection ECU and 2 rear occupant classification sensors. Connect the cable to the negative (-) auxiliary battery terminal. Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . 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. Turn the ignition switch off. NG --> See step 6 OK --> See step 13
  6. CHECK OCCUPANT DETECTION ECU Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU with a known good one. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . HINT: Perform the following inspection using known good parts from another vehicle if possible. Connect the cable to the negative (-) auxiliary battery terminal. Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . 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. Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Return the occupant detection ECU that was installed for testing to its original location. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . NG --> See step 9 OK: Go to next step
  7. REPLACE OCCUPANT DETECTION ECU Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU with a new one. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  8. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  9. REPLACE SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the separate type front seat cushion spring assembly. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Non-removable Headrest. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Removable Headrest). Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  10. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  11. REPLACE SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the separate type front seat cushion spring assembly. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Non-removable Headrest. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Removable Headrest). NOTE: Replace the front seat wire RH at the same time. HINT: When the front seat wire RH has a short to B+, the rear occupant classification sensors will be damaged. Therefore, replace the front seat wire RH and the separate type front seat cushion spring assembly, which includes the rear occupant classification sensors. Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  12. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  13. USE SIMULATION METHOD TO CHECK. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(/toyota/prius-c/i-2011-2015/remont/hoistjack/#introduction)

DTC B1794 is stored when a malfunction is detected in the occupant detection ECU auxiliary battery positive line.

DTC No.DTC Detections ConditionsTrouble Areas
B1794The occupant detection ECU receives an open circuit signal in the occupant detection ECU auxiliary battery positive line. Occupant detection ECU malfunctionAuxiliary battery Wire harness Occupant detection ECU

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1794 is output, perform troubleshooting for the DTC.

Scheme 188

Scheme 188: WIRING DIAGRAM
Scheme 188: WIRING DIAGRAM

Note. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work. Refer to PRECAUTION . Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Scheme 189

Scheme 189: PROCEDURE
Scheme 189: PROCEDURE
  1. CHECK AUXILIARY BATTERY VOLTAGE Measure the voltage of the auxiliary battery. Standard Voltage 11 to 14 V NG --> See step 6 OK: Go to next step
  2. CHECK WIRE HARNESS (SOURCE VOLTAGE) Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Disconnect the connector from the occupant detection ECU. Connect the cable to the negative (-) auxiliary battery terminal. Turn the ignition switch to ON (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition Y3-1 (+B) - Body ground Ignition switch off 11 to 14 V Turn the ignition switch off. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Y3-3 (GND) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Occupant Detection ECU) NG --> REPLACE WIRE HARNESS OK: Go to next step
  3. CHECK DTC Disconnect the cable from the negative (-) auxiliary battery terminal. Connect the connector to the occupant detection ECU. Connect the cable to the negative (-) auxiliary battery terminal. Clear the DTCs stored in the occupant detection ECU. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction) . Turn the ignition switch off. Turn the ignition switch to ON (IG), and wait for at least 10 seconds. Check for DTCs. Refer to «DTC CHECK / CLEAR»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1794 is not output. HINT: Codes other than DTC B1794 may be output at this time, but they are not related to this check. Turn the ignition switch off. NG --> See step 4 OK --> See step 7
  4. REPLACE OCCUPANT DETECTION ECU Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  5. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  6. INSPECT CHARGING SYSTEM AND AUXILIARY BATTERY. Refer to «ON-VEHICLE INSPECTION»(/toyota/prius-c/i-2011-2015/remont/charging-system/#charging-system-inspection)
  7. USE SIMULATION METHOD TO CHECK. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(/toyota/prius-c/i-2011-2015/remont/hoistjack/#introduction)

DTC B1795 is stored when a malfunction is detected in the occupant detection ECU.

DTC No.DTC Detection ConditionTrouble Area
B1795Occupant detection ECU malfunctionOccupant detection ECU

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1795 is output, perform troubleshooting for the DTC.

Note. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work. Refer to PRECAUTION .

  1. REPLACE OCCUPANT DETECTION ECU Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  2. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END

In sleep mode, the occupant detection ECU reads the condition of each sensor while the ignition switch is off.

In this mode, if the occupant detection ECU detects an internal malfunction, DTC B1796 is stored.

DTC No.DTC Detection ConditionTrouble Area
B1796Occupant detection ECU malfunctionOccupant detection ECU

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1796 is output, perform troubleshooting for the DTC.

Note. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work. Refer to PRECAUTION .

  1. REPLACE OCCUPANT DETECTION ECU Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Replace the occupant detection ECU. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  2. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END

The occupant classification system detects the front passenger seat condition. It then displays the front passenger airbag, SRS seat cushion airbag RH and front seat belt pretensioner RH condition (activated/not activated) using the passenger airbag ON/OFF indicator.

HINT

Approximately 6 seconds after the ignition switch is turned to ON (IG), the passenger airbag ON/OFF indicator will indicate ON/OFF depending on the conditions listed below.

Front Passenger Seat ConditionPassenger Airbag ON/OFF IndicatorSRS Warning Light
ON IndicatorOFF Indicator
VacantOFFONOFF
Adult is seated.ONOFFOFF
Child is seated.OFFONOFF
Child restraint system is installed.
Occupant classification system failureOFFONON

Note. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work. Refer to PRECAUTION .

  1. CHECK SRS WARNING LIGHT Turn the ignition switch to ON (IG), and check the SRS warning light condition. HINT: If a passenger airbag ON/OFF indicator malfunction occurs, the SRS warning light does not illuminate. If the light comes on, a DTC is stored. Troubleshoot for the DTC. OK After the primary check period, the SRS warning light goes off. HINT: The primary check is performed for approximately 6 seconds after the ignition switch is turned to ON (IG). NG --> See step 12 OK: Go to next step
  2. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . OK "Zero Point Calibration is complete." and "Sensitivity Check is complete." are displayed. NG --> See step 3 OK --> END
  3. RETIGHTEN FRONT SEAT ASSEMBLY RH BOLT Loosen the 4 installation bolts of the front seat assembly RH. Tighten the 4 installation bolts of the front seat assembly RH to the specified torque. Refer to «INSTALLATION»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Non-removable Headrest. Refer to «INSTALLATION»(/toyota/prius-c/i-2011-2015/remont/seats/#seats-service-information) w/ Removable Headrest). NEXT: Go to next step
  4. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . OK "Zero Point Calibration is complete." and "Sensitivity Check is complete." are displayed. NG --> See step 5 OK --> END
  5. READ VALUE USING TECHSTREAM Using the Techstream, read Data List. Refer to «DATA LIST / ACTIVE TEST»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__data-list-active-test) . Read the display when the passenger side buckle switch is operated. OCCUPANT DETECTION Tester Display Measurement Item / Range Normal Condition Diagnostic Note Passenger Buckle SW Passenger side buckle switch/ Set: The seat belt is fastened Unset: The seat belt is not fastened NG: Data is not determined Set/Unset - OK The Techstream display changes correctly in accordance with the operation of the buckle switch. NG --> See step 9 OK: Go to next step
  6. CHECK CONNECTORS Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Disconnect the connectors from the occupant detection ECU and 2 rear occupant classification sensors. 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
  7. REPLACE OCCUPANT DETECTION ECU Connect the connectors to the 2 rear occupant classification sensors. Replace the occupant detection ECU. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  8. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  9. CHECK CONNECTORS Turn the ignition switch off. Disconnect the cable from the negative (-) auxiliary battery terminal. Disconnect the connectors from the occupant detection ECU and front seat inner belt assembly RH. 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
  10. REPLACE FRONT SEAT INNER BELT ASSEMBLY RH Connect the connector to the occupant detection ECU. Replace the front seat inner belt assembly RH. Refer to «REMOVAL»(/toyota/prius-c/i-2011-2015/remont/restraints-control-systems/#seat-belt-service-information) . Connect the cable to the negative (-) auxiliary battery terminal. NEXT: Go to next step
  11. PERFORM ZERO POINT CALIBRATION AND SENSITIVITY CHECK Using the Techstream, perform Zero Point Calibration and Sensitivity Check. Refer to «INITIALIZATION»(/toyota/prius-c/i-2011-2015/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
  12. GO TO AIRBAG SYSTEM. Refer to «DIAGNOSTIC TROUBLE CODE CHART»(/toyota/prius-c/i-2011-2015/remont/airbag/#supplemental-restraint-system-diagnostics-introduction__diagnostic-trouble-code-chart)

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