Air-Fuel Ratio (A/F) Sensor

2001 Toyota Highlander 2WD L4-2.4L (2AZ-FE)SECTION Air-Fuel Ratio (A/F) Sensor





INSPECT HEATER RESISTANCE OF A/F SENSOR (No.2, No.3 Cylinder side)
a. Disconnect the A/F sensor connector.
b. Using an ohmmeter, measure the resistance between the terminals +B and HT.

Resistance:
1.8 - 3.4 ohms at 20 °C (68 °F)
5.0 - 7.5 ohms at 500 °C (932 °F)

If the resistance is not as specified, replace the sensor.

c. Reconnect the A/F sensor connector.

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

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

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