Auto Repair: Problems That Trigger a Check Engine Light

A vehicle’s check engine light is a very valuable feature. Every vehicle that was manufactured after 1995 is designed with an OB-II diagnostic system. If the check engine light turns on, a scanner can be hooked up to the diagnostic system to extract the trouble code. This helps the motorist or mechanic to track down the root cause of the problem. Here are the most common issues that trigger a check engine light.

Faulty oxygen sensor

Most vehicles are equipped with at least two oxygen sensors. If either of these oxygen sensors fails, the check engine light will likely become illuminated. Not only can a bad oxygen sensor cause a vehicle to fail an emissions test, but it can also lead to a major reduction in fuel efficiency.

Loose gas cap

A loose gas cap can definitely trigger a check engine light. Simply tightening the fuel cap is usually the solution to the problem. Due to the simplicity of the issue, most auto repair shops will not charge the customer to tighten the gas cap. However, the gas cap may need to be replaced if it does not seal properly. Each year, over 100 million gallons of fuel is lost due to ill-fitting gas caps.

Bad catalytic converter

The catalytic converter is one of the most important components on a vehicle. Its primary purpose is to remove toxic pollutants from the exhaust gases. If the catalytic converter is not functioning properly, expect the check engine light to come on. Typically, the catalytic converter’s failure stems from another underlying problem such as a misfiring spark plug. Always replace the converter after fixing the root problem.

Worn out spark plugs

If an engine is not running smoothly, the spark plugs may be the culprit. In order for the engine to have the optimum air-fuel ratio, the sparks plugs need to be in good condition. When replacing the spark plugs, remember to replace the spark plug wires as well. Although some spark plugs are engineered to last up to 100,000 miles, there are many factors that can reduce their lifespan.

Malfunctioning mass airflow sensor

The mass airflow sensor measures the amount of air coming into the engine. This helps the car’s computer to determine the amount of fuel that is needed. A malfunctioning mass airflow sensor can cause a significant reduction in fuel economy.