How to Fake Out an Oxygen Sensor

by Alibaster Smith

The oxygen sensor in your vehicle controls the air to fuel ratio. "Faking out" an oxygen sensor refers to the process of bypassing the sensor so that the sensor does not relay the correct information to the system's computer. This is especially useful if you are trying to manually override the air and fuel settings-also called "tuning" or if you are trying to run your vehicle without a catalytic converter. If you're not experienced with tuning your engine, you'll want expert help. However, faking out an oxygen sensor can easily be done by replacing the legitimate sensor with a dummy sensor. Just be aware that this may or may not be legal in your state.

Step 1

Let the vehicle cool down. You want to allow the vehicle to cool completely for several hours before working on the exhaust system.

Step 2

Disconnect the cable running to the negative battery terminal by loosening the nut on the cable clamp and sliding the clamp off the terminal.

Step 3

Life the vehicle onto jack stands. Place the floor jack under the vehicle's front jack point behind the radiator and jack the vehicle up.

Step 4

Place a jack stand under each of the front pinch welds and lower the vehicle onto the jack stands.

Step 5

Locate the O2 sensor. O2 sensors look like a plug sticking out of the exhaust system. They are normally positioned either in the catalytic converter or before and after it (with two separate sensors).

Step 6

Unplug the electrical wiring from the sensor. Squeeze the release tab and pull the plug out from the sensor housing.

Step 7

Remove the sensor by turning it counterclockwise with an O2 sensor removal tool.

Step 8

Install the dummy O2 sensor (also called an O2 sensor simulator) by turning it clockwise into the exhaust just as though you were installing a regular O2 sensor. Connect the electrical wiring to the dummy sensor.

Step 9

Lower the vehicle to the ground and start the engine. Wait for the check engine light to come on. Your check engine light may or may not come on and stay on. If it flashes or comes on steady, continue to drive the vehicle normally until the check engine light goes off. This is a cycling process that needs to be completed and will typically go off after you have driven the vehicle for several days. Once the cycle has been completed, your vehicle's computer will think the O2 sensor information being provided is legitimate and you will be free to tune the engine as you wish.

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