Why is my Check Engine light after air filter replacement?

My guess is the O2 sensors are ok, but their readings are confusing the ECM b/c the new filter has changed the airflow characteristics to the MAF. Suggest to replace things as they were, buy a new air filter of the same type as the original if necessary.

Can a failed air filter cause an O2 sensor to not work?

The excess filter oil will not make it through to the O2 sensors. There can’t be enough on the filter to load up the O2 sensors. Is it a failed O2 sensor or a failed HEATER for the O2 sensor?

What happens when you replace the air filter?

It is possible that the problems are not related to the air filter and just a coincidence. Catalytic converter fault is dealt with last. Start by replacing oxygen sensors that are indicating fault.

Can a contaminated air filter cause a check engine light?

Since turbocharger performance is monitored by the ECM, lack of boost pressure can cause the ECM to turn on the CEL. It should be noted that the air filter must be extremely restricted to turn the CEL on in a modern, naturally aspirated vehicle. This is because the ECM is good at compensating for lack of air flow.

When to know if your fuel filter is bad?

Fuel filter problems generally won’t happen with proper maintenance. If you start noticing problems with your engine running strangely and experience loss of power and poor gas mileage, the fuel filter is a likely suspect on the fuel side, and an easy one to check off and change.

Where is the fuel filter on a car?

The most common location for a fuel filter is in one of the fuel lines coming from the fuel tank, mounted near the tank on the vehicle’s frame. Several are also located inside the engine compartment, while others are non-serviceable and located within the fuel pump assembly, in the fuel tank.

Can a restricted air filter cause engine problems?

It keeps the undesirables (dirt and debris) out while letting power-producing air in. A restricted air filter can cause many problems, including an illuminated check engine light. Engine airflow performance. Besides keeping contaminants out, an air filter must allow unrestricted airflow into the engine.