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Home >> Lexus >> 2008 >> ES 350 >> 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 the 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.

    OK: PERFORM ZERO POINT CALIBRATION 

    NG: Go to Next Step 

  2. READ VALUE OF DATA LIST (SPECIFIED CONDITION FOR ZERO POINT CALIBRATION) 
    1. Connect Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Using Techstream, read the DATA LIST (See DTC CHECK/CLEAR  ).
      ZERO POINT CALIBRATION SPECIFIED CONDITION

      Item Measurement Item/ Range (Display) Normal Condition Specified Condition for Zero Point Calibration
      RELATIVE PRESS Pressure sensor output/
      Min. 0
      Max 255      		 0 to 210 (reference value) 0 to 2
      THERMISTOR TEMP 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 (36 to 104°F)
      #PRESENT CODES Number of present trouble codes/
      Min. 0
      Max. 255      		 0 0
      #PAST CODES Number of past trouble codes/
      Min.. 0
      Max.. 255      		 0 0

      Result 

      RESULT REFERENCE

      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 condition 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 the DTCs (See DTC CHECK/CLEAR  ).

      OK: 

      DTC B1797 is not output. 

  4. PERFORM ZERO POINT CALIBRATION 
    1. Connect Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Using 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 the 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 negative (-) terminal cable from the battery, and wait for at least 90 seconds.
    3. Replace the front seat cushion assembly (with occupant classification ECU and occupant classification sensor) (See REMOVAL  ).
    4. Connect the negative (-) terminal cable to the battery.
    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 Techstream, check the DTCs of the occupant classification ECU (See DTC CHECK/CLEAR  ).

      OK: 

      DTC is not output. 

  7. PERFORM ZERO POINT CALIBRATION 
    1. Connect Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Using 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 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 the 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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