5 Common Oxygen Sensor Problems

In today’s modern vehicles, oxygen sensor problems are commonly associated with the vehicle’s check-engine light or service-engine light. Lots of vehicle owners take their cars and trucks into shops to get a diagnosis on oxygen sensors that have indicated an issue with the fuel mix for the engine.

What Is an Oxygen Sensor?

The oxygen sensor on a vehicle is part of a greater fuel-emissions system that measures the fuel mix from the fuel injection system. Oxygen sensors work with the catalytic converter, a larger exhaust cleaning and monitoring system, and report on whether the fuel mix is correct, lean, or rich. An incorrect fuel mixture will most likely cause the vehicles check engine light to come on.

Common Problems with Oxygen Sensors

Mechanics have developed a list of frequent problems with oxygen sensors, some of which have less to do with the sensor itself than other parts of the vehicle which can play a role in monitoring fuel conditions.

1. Overheating

Oxygen sensors are made to work at high temperatures. Some of them even have heaters built into them. However one of the biggest problems with the oxygen sensors is their tendency to overheat after high mileage. Oxygen sensors are rated for a specific mileage, often around 100,000, and after that, they can easily go bad and fail due to high temperatures.

2. Spark Plugs and Wires

Some of the trouble codes set by oxygen sensors actually have to do with spark plugs or wires that are not working properly. This kind of engine set up can cause the fuel mix to read differently, and require a mechanic to look at how the oxygen sensors and other parts of the vehicle are affected. This doesn’t mean the shop needs to replace all of the plugs and wires at the first sign of trouble, so drivers are warned to be on the lookout for extremely pricy “comprehensive” diagnosis from an oxygen-sensor code.

3. Mass Airflow Sensor Problems

Experienced mechanics report that sometimes, oxygen sensor issues actually have to do with faulty information coming from another diagnostic part, the mass airflow sensor. This is always an area to check when vague emissions problems are causing warning lights on the dashboard.

4. Malfunctioning Fuel Lines

A malfunction in fuel lines can also cause oxygen sensors to set a lean code. However, this can mean that the required fuel is not getting into the system because of some problem with the fuel pump or other apparatus. a leaky fuel injector can also contribute to a problem that seems to be related to the oxygen sensors.

5. Other OBD-II Problems

In general, the oxygen sensors provide information to a complex engine computer known as the OBD-II system. Any failure to provide a “closed loop” for optimal engine function can cause the OBD-II system to report an error. Many mechanics have stories of repeated dealings with oxygen sensor related codes that were caused by complex problems with the engine computer and its various parts. With oxygen sensors, it may not be enough to just “swap out” these parts when a code sets – some more thoughtful diagnosis and engine work on the part of the shop mechanic may be involved in coming up with the most effective solutions for a customer.