Oxygen sensor



My “CHECK ENGINE” light came on and I took my car into the local repair shop. They informed me that the oxygen sensor was faulty and needed replacing at a charge of $251 plus labor of $224.

Shortly after the repair job I filled my tank with gas and discovered that a new

gas cap had been fitted.

Is there any way of determining whether the new sensor had been installed or did they just change the gas cap?


Take a look at the O2 sensor. Does it look new?


Thanks for the prompt response.
Where do I find the sensor and what does it look like?


How about make model and year of car. If I am not in error, you will find one or two near the converter. OK if I am wrong, sorry, but I have never had to fool with one.


You may have to raise the car to see them. Don’t crawl under the car if it’s supported only by a jack.

There are probably two O2 sensors. They screw into the exhaust pipe, one upstream from the catalytic converter and one downstream.

They are round and have a wire coming from them.

How old is your Impreza, and how many miles on the odometer?


Thanks for the info.
My car is a 1999 model with 134000 miles on the odometer