Oxygen sensors constantly monitor engine emissions and relays this data to the DME. Using these readings the computer determines the proper air/fuel mixture as well as how efficiently the catalyst system is functioning. Symptoms of a failed oxygen sensor range from an EML to poor fuel economy and severe loss of power. A failed upstream sensor will typically cause the engine to run poorly and a failed downstream sensor will typically present as a catalyst efficiency code.
Oxygen sensors measure exhaust oxygen. Their signals are used by the vehicle computer to adjust the air/fuel ratio and test vehicle emissions. Degraded oxygen sensors reduce engine performance and fuel efficiency, and increase harmful tailpipe emissions. They can also turn on the Check Engine Light and cause a car to fail an emissions test.
Show More Show Less