2008 Toyota Prius BaseFACTORY OEM SERVICE PROCEDURE

Knock Sensor: Removal

  1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL 
    CAUTION: Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to prevent airbag and seat belt pretensioner activation.
  2. REMOVE RADIATOR SUPPORT OPENING COVER  (See REMOVAL  )
  3. REMOVE ENGINE UNDER COVER LH 
  4. DRAIN ENGINE COOLANT  (See COOLANT )
  5. REMOVE AIR CLEANER ASSEMBLY  (See REMOVAL  )
  6. REMOVE OIL DIPSTICK GUIDE 
    1. Remove the dipstick.
    2. Disconnect the wire harness clamp.
    3. Remove the bolt and dipstick guide.
      Fig 1: Locating Wire Harness Clamp
      G05189020Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  7. REMOVE INTAKE MANIFOLD SUB-ASSEMBLY 
    1. Disconnect the ventilation hose from the throttle with motor body.
    2. Disconnect the No. 2 ventilation hose.
    3. Disconnect the No. 1 fuel vapor feed hose.
      Fig 2: Locating No. 1 Fuel Vapor Feed Hose
      G05189003Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Disconnect the water by-pass hose.
    5. Disconnect the No. 2 water by-pass hose.
      Fig 3: Locating No. 2 Water By-Pass Hose
      G05189004Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    6. Disconnect the throttle control motor connector.
    7. Disconnect the throttle position sensor connector.
      Fig 4: Locating Throttle Position Sensor Connector
      G05189005Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    8. Disconnect the 3 wire harness clamps.
    9. Disconnect the connector clamp.
    10. Remove the bolt and harness clamp bracket.
      Fig 5: Locating Wire Harness Clamps
      G05189024Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    11. Remove the No. 1 fuel vapor feed hose from the hose clamp.
    12. Remove the 3 bolts, 2 nuts and intake manifold.
      Fig 6: Locating Intake Manifold Bolts And Nuts
      G05189025Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    13. Remove the gasket from the cylinder head.
      Fig 7: Locating Cylinder Head Gasket
      G05189026Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  8. REMOVE KNOCK SENSOR 
    1. Disconnect the knock sensor connector.
    2. Remove the nut and sensor.
      Fig 8: Locating Knock Sensor Connector Nut
      G04828435Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Factory Service Tools

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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.

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