Skip to main content
TechConnect logo Service Bulletins

Oxygen Sensor Replacement Tips

Bulletin 2002

Download PDF


All vehicle applications using an oxygen sensor (O2) or air fuel ratio (AFR) sensor


Oxygen sensors have been required on vehicles beginning with the 1981 model year. Oxygen sensors report the oxygen content in the exhaust so that the engine control module (ECM) can effectively control the emissions levels being emitted from the engine. Adjusting the fuel trims will not only lower the emissions from the engine but also provide peak engine performance under all operating conditions by making infinite adjustments to fuel trims based on information from the sensor.


If an oxygen sensor or air/fuel ratio sensor fails, a diagnostic trouble code will set in the ECM illuminating the Malfunctioning Indication Lamp (MIL). When replacing a sensor an open-end wrench or special socket with an opening on the side (see below) is required to prevent damage to the harness. In northern climates it’s common for the sensor to seize into the pipe due to rust and corrosion. A disadvantage to the special socket is it could flex and strip the hex portion of the old sensor. A suggested tip for removing a seized sensor is to cut the lead from the old sensor which then allows the use of a solid socket or box end wrench permitting more force to remove the sensor without damaging the hex. Another option would be to apply heat around the boss or bung where the seized sensor mounts in the pipe or manifold. If you still have not won, it may be necessary to install a new boss/bung in the pipe or simply replace the pipe or manifold. When reinstalling the new sensor remember to use anti-seize on the threads of the new sensor, clear the trouble code and verify your repair.


For addition support contact the GoTech technical services team at 855-207-5630 M-F 7:30-6:00 CST for assistance.

Some content requires Adobe Acrobat Reader to view.