How to Replace a Ford O2 Sensor
The Ford oxygen (O2) sensor mounts to the exhaust system of the vehicle. It is usually on the exhaust header pipe in front of the catalytic converter (or behind it, in the case of multiple sensors). The sensor utilizes a chemical reaction in the exhaust stream to trigger a voltage signal. The computer picks up the voltage signal and decides whether then engine needs more or less fuel. The computer takes several things into consideration while making the adjustment: air temperature, engine heat, altitude, load and barometric pressure. When the sensor fails, the vehicle can run poorly.
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Things You'll Need
- Code scanner
- Owner's manual
- Floor jack
- Gloves
- Jack stands
- End wrenches
- WD-40
- O2 sensor
- O2 sensor socket (if applicable)
- Socket wrench
- Tie straps
Instructions
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Place the Ford in park or neutral with the emergency brake set. Raise the hood. If you have access to a code scanner, hook it up to the proper connector jack under the dash and turn the key to the "on" position.
The scanner can verify that an 02 sensor needs to be replaced. It also can tell which 02 sensor should be replaced, since there can be as many as four on a vehicle: two mounted forward of the catalytic converter, and two mounted aft of it, for example. The sensors will bolt into the exhaust pipe at either location.
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Disconnect the negative battery cable from its post. Locate the faulty sensor. Make sure you obtain the exact replacement part at your dealership or auto parts store. Raise the vehicle up with a floor jack. Place two jack stands at the front and two at the rear of the vehicle, under the frame.
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Spray WD-40 on the base of the oxygen sensor. Let it soak. Removing the 02 sensor will be easier if the engine has been moderately warmed.
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Trace the O2 sensor wire up toward the engine where it connects to a wire loom. Remove the wire from the connector fastener and bring it down next to the O2 sensor. Spray electrical contact cleaner inside the wire connector socket.
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Put on gloves. Fit the correct-size end wrench around the base sensor shaft nut and turn it counterclockwise until it breaks free. If you have an 02 sensor socket, connect a ratchet wrench to it and thread the wire through the socket slot provided. Turn and loosen it. Once loose, unscrew the sensor by hand.
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Apply a small dab of grease on the new 02 sensor threads and start screwing it in by hand. Finish tightening it with the end wrench or the 02 socket.
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Thread the sensor wire back up to the wire loom connector and snap it back in the socket. Make sure the wire loom has sufficient clearance from the exhaust pipe. Use a tie strap if you need to reposition it and secure it more firmly.
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Reconnect the battery cable at its post. Attach the scanner tool to the connector under the dash. Turn the key to the on position. The scanner will either read "Pass," or it will bring up the 02 sensor trouble code again. If the trouble code appears, erase it and start the engine. Read the scanner for any trouble code. If no trouble codes exist, disconnect the scanner. Use the floor jack to remove the jack stands and lower the vehicle.
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References
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