Oxygen Sensor: Testing and Inspection

1999 Lexus RX 300 AWD V6-3.0L (1MZ-FE)SECTION Testing and Inspection

A/F Ratio Sensor:




INSPECT HEATER RESISTANCE OF A/F SENSORS
a. Disconnect the A/F sensor connector.
b. Using an ohmmeter measure the resistance between terminals +B and HT.
Resistance: 0.8 - 1.4 Ohm at 20°C (68°F)
If the resistance is not as specified, replace the sensor.
Torque: 44 Nm (440 kg.cm, 31 ft.lb)
c. Reconnect the A/F sensor connector.




Components




INSPECT HEATER RESISTANCE OF HEATED OXYGEN SENSOR (Bank 1 Sensor 2)
a. Remove the driver's seat.
b. Take out the floor carpet.
c. Disconnect the oxygen sensor connector.
d. Using an ohmmeter, measure the resistance between the terminals +B and HT.
Resistance: 11 - 16 Ohm at 20°C (68°F)
If the resistance is not as specified, replace the sensor.
Torque: 44 Nm (440 kg.cm, 31 ft.lb)
e. Reconnect the oxygen sensor connector.
f. Reinstall the floor carpet.
g. Reinstall the driver's seat.




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:

  • 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.