How to Check an O2 Sensor
- 1
OBD-II female connection
Turn the ignition in your vehicle in the "ON" or "ACC" position, without cranking the engine. Locate the female connection module to your vehicle. It is usually located in the driver's side foot-well, visible underneath the steering wheel. - 2
Connect the OBD-II (on-board diagnostics) code scanner to the connection module. Once your scanner has verified connection, press the "Scan" button to search for error codes within your vehicle's diagnostic system. A faulty O2 sensor will send an error code to the vehicle. - 3
Write down the error codes your scanner displays. If you do not have any error codes, your O2 sensor is fine. The error code for a faulty O2 sensor varies with each brand of vehicle. Access your computer and visit www.obd-codes.com/trouble_codes. (See the resource below for link.) - 4
Select the manufacturer of your vehicle and input the error code you received. You will receive a description of the code and whether it applies to your O2 sensor or not. If the codes relate to your O2 sensor, it will have to be replaced.
