Why do O2 sensors fail? Since the oxygen sensor is in the exhaust stream, it can become contaminated. Common sources of contamination include an excessively rich fuel mixture condition or oil blow-by in an older engine and engine coolant being burnt in the combustion chamber as a result of an engine gasket leak.
Bad Spark Plug, Wire, or Fuel Injector Because the oxygen in that cylinder isn't burned up, the extra oxygen in that cylinder winds up passing over the O2 sensor. This makes the computer think it's not injecting enough fuel. The computer can become confused about the readings.Jul 7, 2020
Here's something you probably don't know: after clearing the car's computer you will need to drive for about 50 to 100 miles. As you drive your car the computer will monitor all the sensors and register the results. You can use GOFAR to constantly monitor your car diagnostics.
What are the symptoms of a bad downstream oxygen sensor?
- A Glowing Check Engine Light. The bright orange Check Engine light in your dashboard will usually glow if you have a bad oxygen sensor.
- Bad Gas Mileage.
- An Engine That Sounds Rough.
- An Emissions Test Failure.
- An Older Vehicle.
A brand new replacement oxygen sensor can cost you from $20 to $100, depending on the make and year of your car. Taking your car to a mechanic to fix the issue can cost up to $200. In some vehicles, the O2 sensors are more difficult to access and might requre other parts to be removed to replace the sensor.Apr 30, 2019