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Why Is My Check Engine Light On? | Oxygen Sensors

Why Is My Check Engine Light On?

The check engine light turning on can be a cause for concern, but it’s a common issue that many drivers face. Let's explore why this happens and how to address it.

Understanding the Check Engine Light

Your car's check engine light is a signal from the vehicle’s engine control unit (ECU) that something is wrong. Modern cars are equipped with multiple computer modules (anywhere from 30 to 50) that monitor various systems in your vehicle. When something goes amiss, the check engine light illuminates to alert you.

Common Reasons for the Check Engine Light

One often overlooked component that can trigger the check engine light is the oxygen sensor. This sensor plays a critical role in monitoring the exhaust gases and ensuring your engine runs efficiently. Over time, oxygen sensors can become faulty due to exposure to extreme temperatures and contaminants, causing the check engine light to come on.

What Do Oxygen Sensors Do?

1. Front Oxygen Sensors: These sensors help manage the air-fuel ratio by adjusting fuel trims. This ensures your engine runs smoothly.
2. Rear Oxygen Sensors: These sensors monitor the efficiency of the catalytic converter, ensuring it’s reducing harmful emissions properly.

When these sensors malfunction, they can’t relay accurate information to the ECU. This can cause your engine to run too rich (too much fuel) or too lean (not enough fuel), leading to decreased performance, increased emissions, and potential damage to the catalytic converter.

Symptoms of a Faulty Oxygen Sensor

- Decreased fuel efficiency
- Rough engine idle
- Engine misfires
- Increased emissions

Maintenance Tips for Oxygen Sensors

It's recommended to replace your oxygen sensors every 50,000 miles to maintain optimal engine performance. Regular maintenance checks can help prevent issues before they arise. If you're experiencing any of the symptoms mentioned, or if your check engine light is on, it might be time to check your oxygen sensors.

Wayside Garage Maintenance Services

At Wayside Garage, we offer comprehensive maintenance services to ensure your vehicle runs smoothly. Our certified technicians use only the correct sensors for your vehicle, ensuring compatibility and performance.

Maintenance Plan Highlights:
- Every 5-6 Months: Oil & Filter Service, Complimentary Inspection
- Annual: Fuel & Air System Tune-Up, Cabin Air Filter Replacement, Battery Service, Engine Air Filter Replacement, Wheel Alignment, Comprehensive Inspection

By following a regular maintenance schedule, you can extend the lifespan of your vehicle and avoid unexpected issues like a check engine light coming on due to a faulty oxygen sensor.

Schedule Your Service Today

If your check engine light is on, don’t wait. Contact us at Wayside Garage to schedule a maintenance check. Call us at 831-899-2425 or book an appointment online at

Stay ahead of potential issues and keep your car running efficiently with our expert services.


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