Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSTOYOTA2009YARIS S, 4D HATCHBACKREPAIR AND DIAGNOSISRESTRAINTSAIR BAG, SRSSUPPLEMENTAL RESTRAINT SYSTEMOCCUPANT CLASSIFICATION SYSTEMDTC B1785 FRONT OCCUPANT CLASSIFICATION SENSOR LH COLLISION DETECTIONINSPECTION PROCEDURE

2009 Toyota Yaris S, 4D Hatchback

Inspection Procedure

2009 Toyota Yaris S, 4D HatchbackSECTION Inspection Procedure

PERFORM ZERO POINT CALIBRATION
1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to the on position.
3. Using the Techstream, perform the zero point calibration (See INITIALIZATION ).
  OK: COMPLETED is displayed.
NG: Go to step 4

OK: GO TO NEXT STEP
PERFORM SENSITIVITY CHECK
1. Using the Techstream, perform the sensitivity check (See INITIALIZATION ).
  1. Confirm that nothing is placed on the passenger seat.
  2. Confirm that the beginning sensor reading is within the standard range.
    Standard range: -3.2 to 3.2 kg (-7 to 7 lb)
  3. Place a 30 kg (66.14 lb) weight (e.g. a lead mass) onto the front passenger seat.
  4. Confirm that the sensitivity is within the standard range.
    Standard range: 27 to 33 kg (59.52 to 72.75 lb)
    
    HINT:
    
    When performing the sensitivity check, use a solid metal weight (the check result may not be accurate if a liquid weight is used).
NG: Go to step 4

OK: GO TO NEXT STEP
CHECK DTC
1. Turn the ignition switch to the on position.
2. Clear the DTCs stored in the memory (See DTC CHECK/CLEAR ).
  HINT:
  
  First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.
3. Turn the ignition switch to the lock position.
4. Turn the ignition switch to the on position.
5. Check the DTCs (See DTC CHECK/CLEAR ).
  OK: DTC B1785 is not output.
  
  HINT:
  
  Codes other than DTC B1785 may be output at this time, but they are not related to this check.
OK: USE SIMULATION METHOD TO CHECK

NG: GO TO NEXT STEP
REPLACE FRONT SEAT ASSEMBLY RH
1. Turn the ignition switch to the lock position.
2. Disconnect the negative (-) terminal cable from the battery and wait for at least 90 seconds.
3. Replace the front seat assembly RH.
  for Hatchback: REMOVAL
  
  for Sedan: REMOVAL
  
  HINT:
  
  Perform the inspection using parts from a normal vehicle if possible.
PERFORM ZERO POINT CALIBRATION
1. Connect the negative (-) terminal cable to the battery.
2. Connect the Techstream to the DLC3.
3. Turn the ignition switch to the on position.
4. Using the Techstream, perform the zero point calibration (See INITIALIZATION ).
  OK: COMPLETED is displayed.
NG: Go to step 8

OK: GO TO NEXT STEP
PERFORM SENSITIVITY CHECK
1. Using the Techstream, perform the sensitivity check (See INITIALIZATION ).
  1. Confirm that nothing is placed on the passenger seat.
  2. Confirm that the beginning sensor reading is within the standard range.
    Standard range: -3.2 to 3.2 kg (-7 to 7 lb)
  3. Place a 30 kg (66.14 lb) weight (e.g. a lead mass) onto the front passenger seat.
  4. Confirm that the sensitivity is within the standard range.
    Standard range: 27 to 33 kg (59.52 to 72.75 lb)
    
    HINT:
    
    When performing the sensitivity check, use a solid metal weight (the check result may not be accurate if a liquid weight is used).
NG: Go to step 8

OK: GO TO NEXT STEP
CHECK DTC
1. Turn the ignition switch to the on position.
2. Clear the DTCs stored in the memory (See DTC CHECK/CLEAR ).
  HINT:
  
  First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.
3. Turn the ignition switch to the lock position.
4. Turn the ignition switch to the on position.
5. Check the DTCs (See DTC CHECK/CLEAR ).
  OK: DTC B1785 is not output.
  
  HINT:
  
  Codes other than DTC B1785 may be output at this time, but they are not related to this check.
OK: USE SIMULATION METHOD TO CHECK

NG: GO TO NEXT STEP
REPLACE OCCUPANT CLASSIFICATION ECU
1. Turn the ignition switch to the lock position.
2. Disconnect the negative (-) terminal cable from the battery and wait for at least 90 seconds.
3. Replace the occupant classification ECU (See ON-VEHICLE INSPECTION ).
PERFORM ZERO POINT CALIBRATION
1. Connect the negative (-) terminal cable to the battery.
2. Connect the Techstream to the DLC3.
3. Turn the ignition switch to the on position.
4. Using the Techstream, perform the zero point calibration (See INITIALIZATION ).
  OK: COMPLETED is displayed.
PERFORM SENSITIVITY CHECK
1. Using the Techstream, perform the sensitivity check (See INITIALIZATION ).
  1. Confirm that nothing is placed on the passenger seat.
  2. Confirm that the beginning sensor reading is within the standard range.
    Standard range: -3.2 to 3.2 kg (-7 to 7 lb)
  3. Place a 30 kg (66.14 lb) weight (e.g. a lead mass) onto the front passenger seat.
  4. Confirm that the sensitivity is within the standard range.
    Standard range: 27 to 33 kg (59.52 to 72.75 lb)
    
    HINT:
    
    When performing the sensitivity check, use a solid metal weight (the check result may not be accurate if a liquid weight is used).

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.