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Home >> Scion >> 2009 >> xB Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 2 (Supplemental Restraint System) >> Occupant Classification System >> DTC B1797 Calibration Malfunction >> Inspection Procedure

Inspection Procedure

WARNING: This page is about a different car, the 2008 Scion xB. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FOR DTC 
    1. Turn the ignition switch to ON.
    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 ignition switch to OFF.
    5. Turn the ignition switch to ON, 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 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 DIAGNOSIS SYSTEM  )

  2. READ VALUE USING INTELLIGENT TESTER OR TECHSTREAM (SPECIFIED CONDITION FOR ZERO POINT CALIBRATION) 
    1. Connect an intelligent tester or Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    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 - OCCUPANT DETECT

        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 - OCCUPANT DETECTION

        Tester Display Measurement Item/ Range Normal Condition Specified Condition for Zero Point Calibration Diagnostic Note
        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 (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
        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 range of specified conditions 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 ignition switch to ON.
    3. Using the intelligent tester or Techstream, perform zero point calibration (see INITIALIZATION  ).
  4. CHECK FOR DTC 
    1. Turn the ignition switch to ON.
    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 ignition switch to OFF.
    5. Turn the ignition switch to ON.
    6. Check for the DTCs (see 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: Go to step 5 

    OK : END 

  5. PERFORM REGISTRATION BEFORE ECU EXCHANGE 
    1. Connect an intelligent tester or Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Using the intelligent tester or Techstream, save the ECU data from the ECU which was installed on the vehicle (see REGISTRATION  ).
  6. REPLACE FRONT SEAT CUSHION (OCCUPANT DETECTION SENSOR) 
    1. Turn the ignition switch to 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 REMOVAL  ).
    4. Connect the negative (-) terminal cable to the battery.
  7. PERFORM REGISTRATION AFTER ECU EXCHANGE 
    1. Turn the ignition switch to ON.
    2. Using an intelligent tester or Techstream, load the previous ECU data stored in the tester into the new ECU (see REGISTRATION  ).
  8. PERFORM ZERO POINT CALIBRATION 
    1. Using an intelligent tester or Techstream, perform zero point calibration (see INITIALIZATION  ).
    2. Turn the ignition switch to OFF.
    3. Turn the ignition switch to ON.
    4. 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.

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

    NEXT : END 

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