1994 Toyota 22RE Test Oxygen Sensor

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The oxygen sensor on the Toyota 22RE engine can be easily tested to determine if it is faulty before you remove it and replace a perfectly good sensor. It is common that this happens based on the assumption that the sensor is faulty. Do not spend the money and time to remove and replace an O2 sensor until you are sure it is bad. All you need is a digital multimeter to test it. If you do not have one, you can buy one of these very inexpensive tools at most auto-parts stores, department stores or home centers.

Tools Used[edit]

Tools
Digital multimeter

Test Oxygen Sensor[edit]

  • Start the engine in your Toyota and let it run until it is up to normal operating temperature. Run the engine up to 1,200 rpm for about two minutes then remove the connector from the O2 sensor to the wiring harness.
  • Place the positive lead from your digital mutlimeter in to the connector on the O2 sensor. Place the negative lead on the negative post of the battery and with the meter set to the DC voltage scale.
  • Watch the display on the meter. If the reading is fluctuating rapidly between .40 and .60 volts, the O2 sensor is good. If the reading is zero or slow fluctuations outside the range specified, the sensor is likely faulty and should be replaced.
  • Connect the sensor connector to the wiring harness connector and close the hood if the sensor is good. If it is faulty, obtain a replacement senor and change it.

Tips & Warnings[edit]

When placing the positive test lead in the connector on your O2 sensor, you can use either side of the connector as your connection point. The O2 sensor circuit runs in a loop and the test will work either direction.