2012 Toyota Prius TwoFACTORY OEM SERVICE PROCEDURE

Mass Air Flow Meter: Inspection: Inspection

  1. INSPECT MASS AIR FLOW METER 
    1. Perform a visual check for any foreign matter on the platinum hot wire (heater) of the mass air flow meter shown in the illustration.
      Fig 1: Identifying Any Debris On Platinum Hot Wire (Heater) Of The Mass Air Flow
      GTY233713Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Platinum Hot Wire (Heater)

      Result

      There is no foreign matter.

      If the result is not as specified, replace the mass air flow meter.

    2. Measure the resistance according to the value(s) in the table below.
      Fig 2: Identifying Mass Air Flow Meter Connector Terminals
      GTY214688Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Mass Air Flow Meter

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (THA) - 2 (E2) -20°C (-4°F) 13.6 to 18.4 kΩ
      20°C (68°F) 2.21 to 2.69 kΩ
      60°C (140°F) 0.49 to 0.67 kΩ
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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