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Home >> Lexus >> 2009 >> LS 600hL >> Repair and Diagnosis >> External Pages >> Different car >> Section 20 (Supplemental Restraint System) >> Occupant Classification System >> DTC B1797 Calibration Malfunction >> Inspection Procedure

Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: After the power switch is turned OFF, the HDD navigation system requires approximately 6 minutes to record various types of memory and settings. As a result, after turning the power switch OFF, wait 6 minutes or more before disconnecting the cable from the negative (-) battery terminal.
  1. CHECK FOR DTC 
    1. Turn the power switch ON (IG).
    2. Clear the DTCs stored in the occupant classification ECU (see DIAGNOSIS SYSTEM  ).
    3. Clear the DTCs stored in the center airbag sensor (see DTC CHECK / CLEAR  ).
    4. Turn the power switch OFF.
    5. Turn the power switch ON (IG), and wait for at least 10 seconds.
    6. Check for the DTCs (see DIAGNOSIS SYSTEM  ).

      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: Go to step 2 

    OK: USE SIMULATION METHOD TO CHECK  (See TERMINALS OF ECU  )

  2. READ VALUE USING DATA LIST (SPECIFIED CONDITION FOR ZERO POINT CALIBRATION) 
    1. Connect the intelligent tester or Techstream to the DLC3.
    2. Turn the power switch ON (IG)
    3. Using the intelligent tester or Techstream, read the "DATA LIST" or "Data List" (see DATA LIST / ACTIVE TEST  ).
      1. Intelligent tester

        OCCUPANT DETECT: 

        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 are placed on seat cushion and that seat cushion is 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 -
      2. Techstream

        Occupant Detection: 

        DATA LIST

        Tester Display Measurement Item/ Range Normal Condition Specified Condition for Zero Point Calibration Diagnostic Note
        RE Press Pressure sensor output / Min 0, Max 255 0 to 210 (reference value) 0 to 2 -
        Themi 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 are placed on seat cushion and that seat cushion is 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 REFERENCE

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

    B:  Go to step  5

    A: Go to next step 

  3. PERFORM ZERO POINT CALIBRATION 
    1. Connect the intelligent tester or Techstream to the DLC3.
    2. Turn the power switch ON (IG).
    3. Using the intelligent tester or Techstream, perform zero point calibration (see INITIALIZATION  ).
    4. Turn the power switch OFF.
    5. Turn the power switch ON (IG).
    6. Clear the DTCs stored in the memory (see DIAGNOSIS SYSTEM  )

      HINT:

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

  4. CHECK FOR DTC 
    1. Turn the power switch ON (IG)
    2. Clear the DTCs stored in the occupant classification ECU (see DIAGNOSIS SYSTEM  )
    3. Clear the DTCs stored in the center airbag sensor (see DTC CHECK / CLEAR  ).
    4. Turn the power switch OFF.
    5. Turn the power switch ON (IG).
    6. Check for the DTCs (see DIAGNOSIS SYSTEM  ).

      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: Go to step 5 

    OK: END 

  5. REPLACE FRONT SEAT SET (OCCUPANT DETECTION SENSOR) 
    1. Turn the power switch OFF.
    2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
    3. Replace the front seat set (with occupant classification ECU and occupant detection sensor) (see DISASSEMBLY ).
    4. Connect the negative (-) terminal cable to the battery.
    5. Turn the power switch ON (IG).
    6. Clear the DTCs stored in the occupant classification ECU (see DIAGNOSIS SYSTEM  ).
    7. Clear the DTCs stored in the center airbag sensor (see DTC CHECK / CLEAR  )
  6. PERFORM ZERO POINT CALIBRATION 
    1. Connect the intelligent tester or Techstream to the DLC3.
    2. Turn the power switch ON (IG).
    3. Using the intelligent tester or Techstream, perform zero point calibration (see INITIALIZATION  ).
    4. Turn the power switch OFF
    5. Turn the power switch ON (IG).
    6. Clear the DTCs stored in the occupant classification ECU (see DIAGNOSIS SYSTEM  ).

      HINT:

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

  7. PERFORM SENSITIVITY CHECK 
    1. Perform the sensitivity check (see INITIALIZATION  ).

    NEXT: END 

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