Occupant Classification System (diagnostic Codes & Circuit Tests) Lexus IS F I

DESCRIPTION

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

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

HINT

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

Scheme 39

INSPECTION PROCEDURE

HINT

1. If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to access the undersurface of the seat cushion.
2. In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may damage the seat or deform the seat rails. Hold the seat only as necessary.

Scheme 40

Scheme 41

1. CHECK CONNECTORS Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Check that the connectors are properly connected to the occupant classification ECU and the 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 classification ECU and the 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 (-) battery terminal. Turn the engine switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester connection Switch Condition Specified condition T16-13 (BSW) - Body ground Engine switch on (IG) Below 1 V T16-14 (BGND) - Body ground Engine switch on (IG) Below 1 V NG --> REPLACE FRONT SEAT WIRE RH OK: Go to next step
3. CHECK FRONT SEAT WIRE RH (OPEN) Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Using SST, connect terminals 1 (RBE-) and 2 (RBE+) of connector C. NOTE: Do not forcibly insert SST into the terminals of the connector when connecting the wire. SST: 09843-18040 Measure the resistance according to the value(s) in the table below. Standard Resistance Tester connection Condition Specified condition T16-13 (BSW) - T16-14 (BGND) Always Below 1 ohms NG --> REPLACE FRONT SEAT WIRE RH OK: Go to next step
4. CHECK FRONT SEAT WIRE RH (SHORT TO GROUND) Disconnect SST from connector C. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester connection Condition Specified condition T16-13 (BSW) - Body ground Always 1 Mohms or higher T16-14 (BGND) - Body ground Always 1 Mohms or higher NG --> REPLACE FRONT SEAT WIRE RH OK: Go to next step
5. 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 T16-13 (BSW) - T16-14 (BGND) Always 1 Mohms or higher NG --> REPLACE FRONT SEAT WIRE RH OK: Go to next step
6. CHECK DTC Connect the connectors to the occupant classification ECU and the front seat inner belt assembly RH. Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) Turn the engine switch off. Turn the engine switch on (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1771 is not output. HINT: Codes other than B1771 may be output at this time, but they are not related to this check. NG --> See step 7 OK --> See step 10
7. INSPECT FRONT SEAT INNER BELT ASSEMBLY RH Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Replace the front seat inner belt assembly RH with a known good part. Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#seat-belt-service-information) . HINT: Perform an inspection using known good parts from another vehicle if possible. Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1771 is not output. HINT: Codes other than B1771 may be output at this time, but they are not related to this check. NG --> See step 8 OK --> END
8. REPLACE OCCUPANT CLASSIFICATION ECU Connect the Techstream to the DLC3. Turn the engine switch on (IG). Using the Techstream, save the ECU data from the ECU currently installed on the vehicle. Refer to «REGISTRATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__registration) . Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Replace the occupant classification ECU. Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Using the Techstream, load the previous ECU data stored into the new ECU. Refer to «REGISTRATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__registration) . Turn the engine switch off. Turn the engine switch on (IG). Clear the DTCs stored in the memory. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . HINT: If the DTCs are not cleared at this time, past DTC will remain. NEXT: Go to next step
9. PERFORM SENSITIVITY CHECK Perform the sensitivity check. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
10. USE SIMULATION METHOD TO CHECK. Refer to «DIAGNOSIS SYSTEM»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction)

The seat belt tension sensor circuit consists of the occupant classification ECU and the seat belt tension sensor.

The seat belt tension sensor sends the seat belt tension signal to the occupant classification ECU.

DTC B1773 and B1776 are recorded when a malfunction is detected in the seat belt tension sensor circuit.

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1773 and B1776 are output, perform troubleshooting for the DTC.

Scheme 42

HINT

1. If troubleshooting (wire harness inspection) is difficult to perform, remove the passenger seat installation bolts to access the undersurface of the seat cushion.
2. In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may damage the seat or deform the seat rails. Hold the seat only as necessary.

Scheme 43

Scheme 44

Scheme 45

Scheme 46

1. CHECK CONNECTORS Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Check that the connectors are properly connected to the occupant classification ECU and the seat belt tension sensor. 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 classification ECU and the seat belt tension sensor. 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 SEAT BELT TENSION SENSOR CIRCUIT (SHORT TO B+) Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition T16-8 (GBT) - Body ground Engine switch on (IG) Below 1 V T16-16 (BT) - Body ground Engine switch on (IG) Below 1 V T16-17 (VBT) - Body ground Engine switch on (IG) Below 1 V NG --> See step 10 OK: Go to next step
3. CHECK SEAT BELT TENSION SENSOR CIRCUIT (OPEN) Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Using SST, connect terminals 1 (GBT) and 3 (BT), and connect terminals 1 (GBT) and 2 (VBT) of connector E. NOTE: Do not forcibly insert SST into the terminals of the connector when connecting the wire. SST: 09843-18040 Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T16-8 (GBT) - T16-16 (BT) Always Below 1 ohms T16-8 (GBT) - T16-17 (VBT) Always Below 1 ohms NG --> See step 11 OK: Go to next step
4. CHECK SEAT BELT TENSION SENSOR CIRCUIT (SHORT TO GROUND) Disconnect SST from connector E. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T16-8 (GBT) - Body ground Always 1 Mohms or higher T16-16 (BT) - Body ground Always 1 Mohms or higher T16-17 (VBT) - Body ground Always 1 Mohms or higher NG --> See step 12 OK: Go to next step
5. CHECK SEAT BELT TENSION SENSOR CIRCUIT (SHORT) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T16-16 (BT) - T16-8 (GBT) Always 1 Mohms or higher T16-17 (VBT) - T16-8 (GBT) Always 1 Mohms or higher NG --> See step 13 OK: Go to next step
6. CHECK DTC Connect the connectors to the occupant classification ECU and the seat belt tension sensor. Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1773 and B1776 are not output. HINT: Codes other than B1773 and B1776 may be output at this time, but they are not related to this check. NG --> See step 7 OK --> See step 14
7. INSPECT FRONT SEAT OUTER BELT ASSEMBLY RH Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Replace the front seat outer belt assembly RH with a known good part. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . HINT: Perform an inspection using known good parts from another vehicle if possible. Connect the cable from the negative (-) battery terminal. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#seat-belt-service-information) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Turn the engine switch off. Turn the engine switch on (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . OK DTC B1773 and B1776 are not output. HINT: Codes other than B1773 and B1776 may be output at this time, but they are not related to this check. NG --> See step 8 OK --> END
8. REPLACE OCCUPANT CLASSIFICATION ECU Connect the Techstream to the DLC3. Turn the engine switch on (IG). Using the Techstream, save the ECU data from the ECU which has been installed on the vehicle. Refer to «REGISTRATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__registration) . Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Replace the occupant classification ECU. Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Using the Techstream, load the previous ECU data stored into the new ECU. Refer to «REGISTRATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__registration) . Turn the engine switch off. Turn the engine switch on (IG). Clear the DTCs stored in the memory. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . HINT: If the DTCs are not cleared at this time, past DTC will remain. NEXT: Go to next step
9. PERFORM SENSITIVITY CHECK Perform the sensitivity check. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
10. CHECK FRONT SEAT WIRE RH (SHORT TO B+) Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Disconnect the floor wire connector from the front seat wire RH. Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition T16-8 (GBT) - Body ground Engine switch on (IG) Below 1 V T16-16 (BT) - Body ground Engine switch on (IG) Below 1 V T16-17 (VBT) - Body ground Engine switch on (IG) Below 1 V NG --> REPLACE FRONT SEAT WIRE RH OK --> REPLACE FLOOR WIRE
11. CHECK FRONT SEAT WIRE RH (OPEN) Disconnect the floor wire connector from the front seat wire RH. Using SST, connect terminals 5 (BT) and 7 (GBT), and connect terminals 6 (VBT) and 7 (GBT) of connector C. NOTE: Do not forcibly insert SST into the terminals of the connector when connecting the wire. SST: 09843-18040 Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T16-16 (BT) - T16-8 (GBT) Always Below 1 ohms T16-17 (VBT) - T16-8 (GBT) Always Below 1 ohms NG --> REPLACE FRONT SEAT WIRE RH OK --> REPLACE FLOOR WIRE
12. CHECK FRONT SEAT WIRE RH (SHORT TO GROUND) Disconnect the floor wire connector from the front seat wire RH. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T16-8 (GBT) - Body ground Always 1 Mohms or higher T16-16 (BT) - Body ground Always 1 Mohms or higher T16-17 (VBT) - Body ground Always 1 Mohms or higher NG --> REPLACE FRONT SEAT WIRE RH OK --> REPLACE FLOOR WIRE
13. CHECK FRONT SEAT WIRE RH (SHORT) Disconnect the floor wire connector from the front seat wire RH. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T16-16 (BT) - T16-8 (GBT) Always 1 Mohms or higher T16-17 (VBT) - T16-8 (GBT) Always 1 Mohms or higher NG --> REPLACE FRONT SEAT WIRE RH OK --> REPLACE FLOOR WIRE
14. USE SIMULATION METHOD TO CHECK. Refer to «DIAGNOSIS SYSTEM»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction)

The pressure sensor circuit consists of the occupant classification ECU and the occupant classification sensor.

The occupant classification sensor sends the pressure signal to the occupant classification ECU.

DTC B1774 and B1775 are recorded when a malfunction is detected in the pressure sensor circuit.

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1774 and B1775 are output, perform troubleshooting for the DTC.

Scheme 47

HINT

1. If troubleshooting (wire harness inspection) is difficult to perform, remove the passenger seat installation bolts to access the undersurface of the seat cushion.
2. In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may damage the seat or deform the seat rails. Hold the seat only as necessary.
3. After performing the zero point calibration, check for DTCs to confirm that the calibration is completed normally. (If it fails, DTC B1797 will be output.)

Scheme 48

Scheme 49

1. CHECK CONNECTORS Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Check that the connectors are properly connected to the occupant classification ECU and the occupant classification sensor. 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 classification ECU and the occupant classification sensor. 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 (-) battery terminal. Turn the engine switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition T16-6 (PS) - Body ground Engine switch on (IG) Below 1 V T16-7 (VPS) - Body ground Engine switch on (IG) Below 1 V T16-15 (GPS) - Body ground Engine switch on (IG) Below 1 V NG --> REPLACE FRONT SEAT WIRE RH OK: Go to next step
3. CHECK FRONT SEAT WIRE RH (OPEN) Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Using SST, connect terminals 1 (GPS) and 3 (VPS), and connect terminals 2 (PS) and 3 (VPS) of connector C. NOTE: Do not forcibly insert SST into the terminals of the connector when connecting the wire. SST: 09843-18040 Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T16-6 (PS) - T16-7 (VPS) Always Below 1 ohms T16-7 (VPS) - T16-15 (GPS) Always Below 1 ohms NG --> REPLACE FRONT SEAT WIRE RH OK: Go to next step
4. CHECK FRONT SEAT WIRE RH (SHORT TO GROUND) Disconnect SST from connector C. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T16-6 (PS) - Body ground Always 1 Mohms or higher T16-7 (VPS) - Body ground Always 1 Mohms or higher T16-15 (GPS) - Body ground Always 1 Mohms or higher NG --> REPLACE FRONT SEAT WIRE RH OK: Go to next step
5. 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 T16-6 (PS) - T16-15 (GPS) Always 1 Mohms or higher T16-7 (VPS) - T16-15 (GPS) Always 1 Mohms or higher NG --> REPLACE FRONT SEAT WIRE RH OK: Go to next step
6. CHECK DTC Connect the connectors to the occupant classification ECU and the occupant classification sensor. Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTCs B1774 and B1775 are not output. HINT: Codes other than B1774 and B1775 may be output at this time, but they are not related to this check. NG --> See step 7 OK --> See step 11
7. INSPECT OCCUPANT CLASSIFICATION SENSOR (FRONT SEAT CUSHION ASSEMBLY) Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Replace the front seat cushion assembly (with occupant classification ECU and occupant classification sensor) with a known good part. Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-service-information) . HINT: Perform an inspection using known good parts from another vehicle if possible. Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Check the DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1774 and B1775 are not output. HINT: Codes other than B1774 and B1775 may be output at this time, but they are not related to this check. NEXT: Go to next step
8. PERFORM ZERO POINT CALIBRATION Connect the Techstream to the DLC3. Turn the engine switch on (IG). Using the Techstream, perform the zero point calibration. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . Turn the engine switch off. Turn the engine switch on (IG). Clear the DTCs stored in the memory. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . HINT: If DTC is not cleared at this time, past DTC will remain. NEXT: Go to next step
9. CHECK DTC HINT: Check that the zero point calibration is completed normally. If any of the following conditions is met, DTC B1797 will be output (Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) ): Zero point calibration is performed when the conditions for the calibration are not satisfied. Zero point calibration has failed. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1797 is not output. NG --> See step 12 OK: Go to next step
10. PERFORM SENSITIVITY CHECK Perform the sensitivity check. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
11. USE SIMULATION METHOD TO CHECK. Refer to «DIAGNOSIS SYSTEM»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction)
12. GO TO DTC B1797. Refer to «DTC B1797: Calibration Malfunction»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostic-codes-circuit-tests)

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

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

HINT

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

Scheme 50

HINT

1. If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to access the undersurface of the seat cushion.
2. In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may damage the seat or deform the seat rails. Hold the seat only as necessary.

Scheme 51

Scheme 52

Scheme 53

Scheme 54

1. CHECK CONNECTORS Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds. Check that the connectors are properly connected to the occupant classification ECU and the center airbag sensor assembly. 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 center airbag sensor assembly and the occupant classification 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 front seat wire RH and floor wire. Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition T16-11 (FSR+) - Body ground Engine switch on (IG) Below 1 V T16-12 (FSR-) - Body ground Engine switch on (IG) Below 1 V NG --> See step 12 OK: Go to next step
3. CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (OPEN) Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds. Using SST, connect terminals 12 (FSP+) and 13 (FSP-) of connector B. NOTE: Do not forcibly insert SST into the terminals of the connector when connecting the wire. SST: 09843-18040 Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T16-11 (FSR+) - T16-12 (FSR-) Always Below 1 ohms NG --> See step 13 OK: Go to next step
4. CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (SHORT) Disconnect SST from connector B. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T16-11 (FSR+) - T16-12 (FSR-) Always 1 Mohms or higher NG --> See step 14 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 T16-11 (FSR+) - Body ground Always 1 Mohms or higher T16-12 (FSR-) - Body ground Always 1 Mohms or higher NG --> See step 15 OK: Go to next step
6. RECHECK DTC Connect the connectors to the occupant classification ECU and the center airbag sensor assembly. Connect the Techstream to the DLC3. Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Using the Techstream, check for DTCs of the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/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. NG --> See step 7 OK --> See step 16
7. REPLACE OCCUPANT CLASSIFICATION ECU Connect the Techstream to the DLC3. Turn the engine switch on (IG). Using the Techstream, save the ECU data from the ECU currently installed on the vehicle. Refer to «REGISTRATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__registration) . Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Replace the occupant classification ECU. Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Using the Techstream, load the previous ECU data stored into the new ECU. Refer to «REGISTRATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__registration) . Turn the engine switch off. Turn the engine switch on (IG). Clear the DTCs stored in the memory. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . HINT: If the DTCs are not cleared at this time, past DTCs will remain. NEXT: Go to next step
8. RECHECK DTC Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Using the Techstream, check for DTCs of the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/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. NG --> See step 10 OK: Go to next step
9. PERFORM SENSITIVITY CHECK Perform the sensitivity check. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
10. REPLACE CENTER AIRBAG SENSOR ASSEMBLY Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds. Replace the center airbag sensor assembly. Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-service-information) . NEXT: Go to next step
11. PERFORM SENSITIVITY CHECK Perform the sensitivity check. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
12. CHECK FLOOR WIRE (SHORT TO B+) Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds. Disconnect the front seat wire RH connector from the floor wire. Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition PT2-3 (FSR+) - Body ground Engine switch on (IG) Below 1 V PT2-8 (FSR-) - Body ground Engine switch on (IG) Below 1 V NG --> REPLACE FLOOR WIRE OK --> REPLACE FRONT SEAT WIRE RH
13. CHECK FLOOR WIRE (OPEN) Disconnect the front seat wire RH connector from the floor wire. HINT: SST 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 PT2-3 (FSR+) - PT2-8 (FSR-) Always Below 1 ohms NG --> REPLACE FLOOR WIRE OK --> REPLACE FRONT SEAT WIRE RH
14. 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 PT2-3 (FSR+) - PT2-8 (FSR-) Always 1 Mohms or higher NG --> REPLACE FLOOR WIRE OK --> REPLACE FRONT SEAT WIRE RH
15. 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 PT2-3 (FSR+) - Body ground Always 1 Mohms or higher PT2-8 (FSR-) - Body ground Always 1 Mohms or higher NG --> REPLACE FLOOR WIRE OK --> REPLACE FRONT SEAT WIRE RH
16. USE SIMULATION METHOD TO CHECK. Refer to «DIAGNOSIS SYSTEM»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction)

DTC B1795 is recorded when a malfunction is detected in the occupant classification ECU.

HINT

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

HINT

1. If troubleshooting (wire harness inspection) is difficult to perform, remove the front passenger seat installation bolts to access the undersurface of the seat cushion.
2. In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may damage the seat or deform the seat rails. Hold the seat only as necessary.

PROCEDURE

1. CHECK DTC Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG), and wait for at least 10 seconds. Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1795 is not output. HINT: Codes other than B1795 may be output at this time, but they are not related to this check. NG --> See step 2 OK --> See step 4
2. REPLACE OCCUPANT CLASSIFICATION ECU Connect the Techstream to the DLC3. Turn the engine switch on (IG). Using the Techstream, save the ECU data from the ECU which has been installed on the vehicle. Refer to «REGISTRATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__registration) . Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Replace the occupant classification ECU. Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Using the Techstream, load the previous ECU data stored into the new ECU. Refer to «REGISTRATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__registration) . Turn the engine switch off. Turn the engine switch on (IG). Clear the DTCs stored in the memory. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . HINT: If the DTCs are not cleared at this time, past DTC will remain. NEXT: Go to next step
3. PERFORM SENSITIVITY CHECK Perform the sensitivity check. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
4. USE SIMULATION METHOD TO CHECK. Refer to «DIAGNOSIS SYSTEM»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction)

DTC B1797 is output when the following conditions are met

1. Zero point calibration is performed when the conditions for the calibration are not satisfied.

1. Zero point calibration has failed.

CONDITION FOR THE ZERO POINT CALIBRATION

HINT

When DTC B1650/32 is detected as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant classification ECU. When DTC B1797 is output, perform troubleshooting for the DTC.

1. CHECK DTC Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG), and wait for at least 10 seconds. Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1797 is not output. HINT: Codes other than B1797 may be output at this time, but they are not related to this check. NG --> See step 2 OK --> See step 10
2. READ VALUE USING DATA LIST (SPECIFIED CONDITION FOR ZERO POINT CALIBRATION) Connect the Techstream to the DLC3. Turn the engine switch on (IG). Using the Techstream, read the Data List. Refer to «DATA LIST / ACTIVE TEST»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__data-list-active-test) . Tester Display Measurement Item/Range Normal Condition Specified Condition for Zero Point Calibration Pressure Sensor Output Pressure sensor output/ Min.: 0 Max.: 255 0 to 210 (reference value) 0 to 2 Thermistor Temperature Output Thermistor temperature output/ Min.: -40°C (-40°F) Max.: 90°C (194°F) -40 to 85°C (-40 to 185°F) 3 to 40°C (37 to 104°F) Number of Present DTC Number of present trouble codes/ Min.: 0 Max.: 255 0 0 Number of Past DTC Number of past trouble codes/ Min.: 0 Max.: 255 0 0 Result Result Proceed to All items correspond to the range of specified condition for zero point calibration. A Thermistor Temperature Output does not correspond to the range of specified condition for zero point calibration. B B --> See step 6 A: Go to next step
3. CHECK DTC HINT: Check that the zero point calibration is completed normally. If any of the following conditions is met, DTC B1797 will be output (Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) ). Zero point calibration is performed when the calibration conditions are not satisfied. Zero point calibration has failed. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1797 is not output. NEXT: Go to next step
4. PERFORM ZERO POINT CALIBRATION Connect the Techstream to the DLC3. Turn the engine switch on (IG). Using the Techstream, perform the zero point calibration. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . Turn the engine switch off. Turn the engine switch on (IG). Clear the DTCs stored in the memory. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . HINT: If the DTCs are not cleared at this time, past DTCs will remain. NEXT: Go to next step
5. CHECK DTC Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1797 is not output. HINT: Codes other than B1797 may be output at this time, but they are not related to this check. NEXT --> END
6. REPLACE OCCUPANT CLASSIFICATION SENSOR (FRONT SEAT CUSHION ASSEMBLY) Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Replace the front seat cushion assembly (with occupant classification ECU and occupant classification sensor). Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Using the Techstream, check for DTCs of the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC is not output. NEXT: Go to next step
7. PERFORM ZERO POINT CALIBRATION Connect the Techstream to the DLC3. Turn the engine switch on (IG). Using the Techstream, perform the zero point calibration. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . Turn the engine switch off. Turn the engine switch on (IG). Clear DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . HINT: If the DTCs are not cleared at this time, past DTCs will remain. NEXT: Go to next step
8. CHECK DTC Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1797 is not output. NEXT: Go to next step
9. PERFORM SENSITIVITY CHECK Perform the sensitivity check. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
10. PERFORM ZERO POINT CALIBRATION. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization)

The occupant classification system detects the front passenger seat condition. It then informs the front passenger airbag, front passenger side knee airbag, front seat side airbag RH and front seat belt pretensioner RH condition (activated/not activated) by the passenger airbag ON/OFF indicator.

HINT

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

HINT

When the indicator is malfunctioning, if the SRS warning light is off, follow the procedures below as a DTC is not output. If the SRS warning light is on, a DTC is output. Troubleshoot for the output DTC.

1. PERFORM ZERO POINT CALIBRATION Connect the Techstream to the DLC3. Turn the engine switch on (IG). Using the Techstream, perform the zero point calibration. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . Turn the engine switch off. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . HINT: If the DTCs are not cleared at this time, past DTCs will remain. NEXT: Go to next step
2. CHECK DTC Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Check for DTCs of the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC B1797 is not output. HINT: Codes other than DTC B1797 may be output at this time, but they are not related to this check. NG --> See step 10 OK: Go to next step
3. CHECK PASSENGER AIRBAG ON/OFF INDICATOR (PERFORM SENSITIVITY CHECK) Perform the sensitivity check. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NG --> See step 4 OK --> END
4. READ VALUE USING DATA LIST (PASSENGER SIDE BUCKLE SWITCH) Turn the engine switch on (IG). Using the Techstream, read the Data List. Refer to «DATA LIST / ACTIVE TEST»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__data-list-active-test) . Read the the display when the passenger side buckle switch is operated. Tester Display Measurement Item/Range Normal Condition Diagnostic Note Passenger Buckle SW Buckle switch (Passenger side)/ Unset: The seat belt is not fastened Set: The seat belt is fastened NG: Data is not determined Unset/Set - OK The tester display changes correctly in accordance with the operation of the buckle switch. NG --> See step 11 OK: Go to next step
5. READ VALUE USING DATA LIST (SEAT BELT TENSION SENSOR) Fasten the passenger side seat belt. Turn the engine switch on (IG). Using the Techstream, read the value of the Data List. Refer to «DATA LIST / ACTIVE TEST»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__data-list-active-test) . Tester Display Measurement Item/Range Normal Condition Diagnostic Note Filtered Pressure Sensor Output Filtered belt tension output/ Min.: 0 Max.: 255 39 to 64 (no load) - OK When there is no tension on the belt, 39 to 64 is displayed on the Techstream. NG --> See step 12 OK: Go to next step
6. CHECK CONNECTORS Disconnect the connectors from the occupant classification ECU and the occupant classification sensor. Check that the terminals of 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 FRONT SEAT CUSHION ASSEMBLY Turn the engine switch off. Disconnect the cable from the negative (-) battery terminal. Replace the front seat cushion assembly (with occupant classification ECU and occupant classification sensor). Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-service-information) . Connect the cable to the negative (-) battery terminal. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . Clear the DTCs stored in the center airbag sensor assembly. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#supplemental-restraint-system-diagnostics-introduction) . Turn the engine switch off. Turn the engine switch on (IG). Check for DTCs. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . OK DTC is not output. NEXT: Go to next step
8. PERFORM ZERO POINT CALIBRATION Connect the Techstream to the DLC3. Turn the engine switch on (IG). Using the Techstream, perform the zero point calibration. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . Turn the engine switch off. Turn the engine switch on (IG). Clear the DTCs stored in the occupant classification ECU. Refer to «DTC CHECK / CLEAR»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__dtc-check-clear) . HINT: If the DTCs are not cleared at this time, past DTCs will remain. NEXT: Go to next step
9. PERFORM SENSITIVITY CHECK Perform the sensitivity check. Refer to «INITIALIZATION»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostics-introduction__initialization) . NEXT --> END
10. GO TO DTC B1797. Refer to «DTC B1797: Calibration Malfunction»(/lexus/is-f/i-2007-2014/remont/airbag/#occupant-classification-system-diagnostic-codes-circuit-tests)
11. REPLACE FRONT SEAT INNER BELT ASSEMBLY RH. Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#seat-belt-service-information)
12. REPLACE FRONT SEAT OUTER BELT ASSEMBLY RH. Refer to «REMOVAL»(/lexus/is-f/i-2007-2014/remont/restraints-control-systems/#seat-belt-service-information)

See also:
• DTC CHECK / CLEAR
• DTC CHECK / CLEAR
• REMOVAL
• REGISTRATION
• REMOVAL
• INITIALIZATION
• DIAGNOSIS SYSTEM
• DATA LIST / ACTIVE TEST
• DTC B1797: Calibration Malfunction