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Home >> Lexus >> 2007 >> GS 350 AWD >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Supplemental Restraint System >> Occupant Classification System >> DTC B1797 Calibration Malfunction >> Inspection Procedure

Inspection Procedure

  1. CHECK FOR 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 (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 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 the intelligent tester (with CAN VIM) to the DLC3.
    2. Turn the engine switch on (IG).
    3. Using the intelligent tester, read the DATA LIST (see DATA LIST / ACTIVE TEST ).

      Occupant classification ECU: 

      DATA LIST

      Tester Display Measurement Item/Range Normal Condition Specified Condition for Zero Point Calibration Diagnostic Note
      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)      		 If value is outside range of Specified Condition for Zero Point Calibration, check whether any objects placed on seat cushion and that seat cushion fitted correctly
      #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 CHART

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

    B:  Go to step  6

    A: Go to next step 

  3. CHECK FOR 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 : see ).

    • 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 (see DTC CHECK / CLEAR ).
    4. Turn the engine switch off.
    5. Turn the engine switch on (IG).
    6. Check for the DTCs (see DTC CHECK / CLEAR ).

      OK: 

      DTC B1797 is not output. 

  4. PERFORM ZERO POINT CALIBRATION 
    1. Connect the intelligent tester (with CAN VIM) to the DLC3.
    2. Turn the engine switch on (IG).
    3. Using the intelligent tester, 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 FOR 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 (see DTC CHECK / CLEAR ).
    4. Turn the engine switch off.
    5. Turn the engine switch on (IG).
    6. Check for 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 DETECTION 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 (with occupant classification ECU and occupant detection sensor) (see DISASSEMBLY ).
    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 (see DTC CHECK / CLEAR ).
    8. Turn the engine switch off.
    9. Turn the engine switch on (IG).
    10. Using the intelligent tester, check for the DTCs of the occupant classification ECU (see DTC CHECK / CLEAR ).

      OK: 

      DTC is not output. 

  7. PERFORM ZERO POINT CALIBRATION 
    1. Connect the intelligent tester (with CAN VIM) to the DLC3.
    2. Turn the engine switch on (IG).
    3. Using the intelligent tester, 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 FOR 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 (see DTC CHECK / CLEAR ).
    4. Turn the engine switch off.
    5. Turn the engine switch on (IG).
    6. Check for 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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