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Home › Lexus › 2008 › IS F › Repair and Diagnosis › Restraints › Air Bag, SRS › Supplemental Restraint System › Occupant Classification System › DTC B1797 Calibration Malfunction › Inspection Procedure

Inspection Procedure

  1. CHECK DTC 
    1. Turn the engine switch on (IG)
    2. Clear the DTCs stored in the occupant classification ECU (See DTC CHECK / CLEAR  )
    3. Clear the DTCs stored in the center airbag sensor assembly (See DTC CHECK / CLEAR  )
    4. Turn the engine switch off.
    5. Turn the engine switch on (IG), and wait for at least 10 seconds.
    6. Check for DTCs (See 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: Go to step 2 

    OK: PERFORM ZERO POINT CALIBRATION  (See INITIALIZATION  )

  2. READ VALUE USING DATA LIST (SPECIFIED CONDITION FOR ZERO POINT CALIBRATION) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Using the Techstream, read the Data List (See DATA LIST / ACTIVE TEST  ).
      MEASUREMENT ITEM CHART

      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 CHART

      Result Proceed to
      All items correspond to the range of specified condition for zero point calibration. A
      THERMISTOR TEMP does not correspond to the range of specified condition for zero point calibration. B

    B: Go to 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  ).

    • Zero point calibration is performed when the calibration conditions are not satisfied.
    • Zero point calibration has failed.
    1. Turn the engine switch on (IG).
    2. Clear the DTCs stored in the occupant classification ECU (See DTC CHECK / CLEAR  ).
    3. Clear the DTCs stored in the center airbag sensor assembly (See DTC CHECK / CLEAR  )
    4. Turn the engine switch off.
    5. Turn the engine switch on (IG).
    6. Check for DTCs (See DTC CHECK / CLEAR  ).

      OK: DTC B1797 is not output. 

  4. PERFORM ZERO POINT CALIBRATION 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG)
    3. Using the Techstream, perform the zero point calibration (See INITIALIZATION  )
    4. Turn the engine switch off
    5. Turn the engine switch on (IG)
    6. Clear the DTCs stored in the memory (See DTC CHECK / CLEAR  )

      HINT

      If the DTCs are not cleared at this time, past DTCs will remain.

  5. CHECK DTC 
    1. Turn the engine switch on (IG)
    2. Clear the DTCs stored in the occupant classification ECU (See DTC CHECK / CLEAR  )
    3. Clear the DTCs stored in the center airbag sensor assembly (See DTC CHECK / CLEAR  )
    4. Turn the engine switch off
    5. Turn the engine switch on (IG)
    6. Check for DTCs (See 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) 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal
    3. Replace the front seat cushion assembly (with occupant classification ECU and occupant classification sensor) (See REMOVAL  )
    4. Connect the cable to the negative (-) battery terminal
    5. Turn the engine switch on (IG)
    6. Clear the DTCs stored in the occupant classification ECU (See DTC CHECK / CLEAR  )
    7. Clear the DTCs stored in the center airbag sensor assembly (See DTC CHECK / CLEAR  )
    8. Turn the engine switch off.
    9. Turn the engine switch on (IG).
    10. Using the Techstream, check for DTCs of the occupant classification ECU (See DTC CHECK / CLEAR  )

      OK: DTC is not output. 

  7. PERFORM ZERO POINT CALIBRATION 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG)
    3. Using the Techstream, perform the zero point calibration (See INITIALIZATION  )
    4. Turn the engine switch off.
    5. Turn the engine switch on (IG)
    6. Clear DTCs stored in the occupant classification ECU (See DTC CHECK / CLEAR  ).

      HINT

      If the DTCs are not cleared at this time, past DTCs will remain

  8. CHECK DTC 
    1. Turn the engine switch on (IG).
    2. Clear the DTCs stored in the occupant classification ECU (See DTC CHECK / CLEAR  )
    3. Clear the DTCs stored in the center airbag sensor assembly (See DTC CHECK / CLEAR  )
    4. Turn the engine switch off.
    5. Turn the engine switch on (IG)
    6. Check for DTCs (See DTC CHECK / CLEAR  ).

      OK: DTC B1797 is not output. 

  9. PERFORM SENSITIVITY CHECK 
    1. Perform the sensitivity check (See INITIALIZATION  )

    NEXT: END 

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