An oxygen sensor is a designed to monitor the emissions before they enter the catalytic convertor. While a Ford Ranger’s oxygen sensor rarely fails on its own, a malfunction in the fuel system can lead to a contaminated oxygen sensor, which will need to be replaced. The sensor is located in the exhaust pipe between the manifold and the catalytic converter. This job is best performed with a cold engine, as the sensor is screwed into the exhaust which can easily deliver third degree burns if contacted when hot. With basic mechanical inclination this job can be performed in less than an hour.
Tools Used: Tools, Floor jack, Jack stands, Pocket screwdriver, Box wrenches, Penetrating oil and rag (optional), Anti seize compound, Replacement oxygen sensor
Remove Oxygen Sensor
Raise the front end of the Ranger with the floor jack and support it on the jack stands. Climb under the front end and disconnect the oxygen sensor wiring harness, often referred to as a pigtail, from the main engine harness. You may need a pocket screwdriver to disconnect the pigtail’s clip. Use the box wrench to remove the oxygen sensor form the exhaust. If the sensor will not come out easily, spray some penetrating oil on it and let the oil soak in for about fifteen minutes and then try again. Make sure to wipe any oil residue off the exhaust pipe, as it can ignite when the exhaust reaches operating temperature.
Compare the old sensor to the replacement sensor before beginning the installation. Make sure they are identical before installing the new one. Place some anti seize compound on the threads of the replacement sensor. Thread the sensor in by hand and then tighten it down with the box wrench. Connect the pigtail to the engine harness. Climb out and lower the Ranger back onto the ground.