There are number of ways to address a glowing check engine light. They range from using black electrical tape to cover over the engine icon to driving to the nearest repair shop and camping out in the waiting room. But whatever your approach, you owe it to yourself to understand what is at stake when the light is triggered by a failed oxygen sensor.
These sensors monitor unburned oxygen in the exhaust and send reports back to the vehicle's powertrain control module (PCM) that indicate how efficiently the car is burning its fuel. This all has an impact on the performance, fuel economy, and emissions of the vehicle. This is all done by the PCM on the fly as the engine is running by controlling fuel delivery through the fuel injectors.
Bosch developed oxygen sensors in the 1970s to deal with exhaust emissions and according to a company product manager quoted by the Car Care News Service, it has produced 500 million of the bullet-shaped parts.
Vehicles can have as many as four O2 sensors placed strategically within the exhaust system to be able to monitor the level of oxygen in the exhaust stream. When the O2 sensor wears out and fails to send an accurate signal to the PCM, the recipe for the right fuel mixture gets distorted causing poor performance, decreased fuel economy, and possibly damage to the catalytic converter and other important parts of the vehicle.
Many times there are no discernible changes in the way the car drives and that is the insidious part of an O2 sensor failure that causes a check engine light to illuminate. The standard advice contained in the owner's manual is to have the car checked by a professional with an additional warning that once the check engine light begins to blink the condition has become very urgent.
Ignoring a check engine light should not be an option since one of the most common causes is an underperforming oxygen sensor. Postponing the replacement of this part could lead to much more costly repairs later on and most likely is adversely affecting your gas mileage in the meantime.
Once you understand a little of the technology behind the purpose of the oxygen sensor, you can understand why it doesn't make sense to procrastinate resolving a check engine light that might be the result of a failed O2 sensor.