What are issues that commonly trigger the check engine light?

Novato Auto Service • January 6, 2025
A person is working on a car engine with a wrench.

The check engine light is a sign that your vehicle’s onboard diagnostic system has detected an issue that needs attention. At Novato Auto Service, we provide expert check engine light diagnostics and repair in the greater Novato, CA area. Here’s a look at five common check engine light triggers. 


Faulty Oxygen Sensor

The oxygen sensor plays a critical role in monitoring the balance of air and fuel in your engine. If the sensor becomes damaged or malfunctions, it can cause inaccurate readings, leading to reduced fuel-efficiency and increased emissions. A faulty oxygen sensor is one of the most frequent triggers for the check engine light and should be replaced as soon as possible to maintain optimal engine performance.


Loose or Damaged Gas Cap

It may seem surprising, but a loose or damaged gas cap is a common reason the check engine light comes on. The gas cap seals the fuel system, and if it isn’t tightly secured, fuel may evaporate before your engine gets the chance to use it.


Failing Catalytic Converter

The catalytic converter helps reduce harmful emissions by converting pollutants into less harmful gases. A failing catalytic converter can also lead to poor performance and increased emissions, making immediate attention important.


Malfunctioning Mass Airflow Sensor

The mass airflow (MAF) sensor measures the amount of air entering the engine and helps regulate the air-to-fuel ratio. If the sensor fails, your engine may run too rich or too lean, leading to poor fuel-economy and potential engine stalling. 


Worn or Misfiring Spark Plugs

Spark plugs are essential for igniting the fuel-air mixture in your engine’s cylinders. When spark plugs wear out or misfire, they can cause engine performance issues such as rough idling, reduced power, and poor fuel-efficiency. Worn spark plugs are a frequent reason for the check engine light and should be replaced as part of your vehicle’s regular maintenance.


Check Engine Light Repair in Novato, CA

For auto repair in Novato and the surrounding area, contact Novato Auto Service at 415-598-1488. Feel free to give us a call to make an appointment!

By Novato Auto Service January 4, 2026
Few dashboard warnings cause as much concern as the check engine light. While it can signal a serious problem, it often points to common issues that still require timely attention. Ignoring the light may allow minor problems to turn into expensive repairs. Understanding some of the most frequent reasons your check engine light comes on can help you take the right steps to protect your vehicle. At Novato Auto Service, we provide expert check engine light diagnostics and repair in the greater Novato, CA area. Here’s a look at four common check engine light triggers that should be quickly addressed. Oxygen Sensor Failure Oxygen sensors measure how much unburned oxygen is present in the exhaust and help the engine adjust the air-fuel mixture. When an oxygen sensor fails, the engine may burn too much fuel, reducing efficiency and increasing emissions. Over time, a faulty sensor can also damage the catalytic converter, making early diagnosis and replacement important. Malfunctioning Mass Airflow Sensor The mass airflow sensor monitors the amount of air entering the engine and helps ensure the proper fuel mixture is delivered. If this sensor fails, the engine may hesitate, idle roughly, or stall. Fuel economy often suffers as well. A malfunctioning mass airflow sensor can trigger the check engine light and should be addressed promptly to restore proper performance. Catalytic Converter Problems The catalytic converter reduces harmful emissions by converting exhaust gases into less toxic substances. When it begins to fail, the check engine light may illuminate alongside symptoms such as reduced power or a sulfur-like odor. Worn Spark Plugs or Ignition Coils Spark plugs and ignition coils are responsible for igniting the air-fuel mixture inside the engine. When they wear out or fail, misfires can occur, leading to rough running and poor acceleration. These misfires frequently trigger the check engine light and can cause further problems if ignored. Check Engine Light Repair in Novato, CA For expert auto repair in Novato and the surrounding area, contact Novato Auto Service at (415) 598-1488. Feel free to give us a call to make an appointment for car care in greater Novato!
By Novato Auto Service December 4, 2025
Your vehicle’s suspension system is designed to provide a smooth, controlled ride while keeping your tires firmly connected to the road. When everything is working properly, you enjoy stability, comfort, and reliable handling. But when suspension components begin to wear out or fail, the symptoms can quickly affect your safety. Ignoring early warning signs can lead to more serious damage, higher repair costs, and increased risk on the road. At Novato Auto Service, we provide expert suspension repair in the greater Novato, CA area. Here are four warning signs that your vehicle may need suspension repair right away. A Rough Ride One of the most noticeable signs of suspension trouble is a ride that suddenly feels rougher than usual. If your vehicle bounces excessively after hitting bumps or dips, your shocks or struts may be worn out. These components are designed to absorb impact and keep your tires stable. When they fail, the vehicle becomes harder to control, and the additional bouncing can cause uneven tire wear and further stress on the suspension system. Difficulty Steering or Poor Handling If your steering feels loose, stiff, or less responsive, this could point to a suspension issue. Problems such as worn control arm bushings, damaged ball joints, or deteriorating tie rods can make the vehicle difficult to steer. You may also notice drifting or pulling to one side while driving, even on straight roads. These symptoms make it crucial to seek repairs immediately. Uneven Tire Wear Your tires provide an excellent window into the condition of your suspension. When suspension components fail to keep the wheels aligned, uneven tire wear begins to develop. You might notice bald spots or one tire wearing down much faster than the others. If left unresolved, this uneven wear not only shortens tire life, but also reduces traction and can increase the likelihood of a blowout. Addressing suspension issues early can help protect your tires and enhance your vehicle’s overall safety. Clunking, Squeaking, or Other Strange Noises Unusual noises coming from beneath your vehicle are often signs of failing suspension parts. These noises may grow louder over time as components continue to wear. Since failing suspension parts can cause dangerous driving conditions, it’s important to have these noises diagnosed quickly. Suspension Repair in Novato, CA When you need auto repair in Novato and the surrounding area, contact Novato Auto Service at  415-598-1488  . Feel free to give us a call to make an appointment!
Hands installing a car brake rotor on a vehicle, workshop setting.
By Novato Auto Service November 7, 2025
Reliable brakes help ensure that you can stop quickly and protect yourself and others on the road. However, like any part of your vehicle, your brakes require regular care and attention to stay in top condition. Neglecting brake maintenance can lead to reduced performance and dangerous situations. At Novato Auto Service, we provide expert brake service in the greater Novato, CA area. Here are five tips to help keep your brakes in optimal health. Have Your Brakes Inspected Regularly Routine inspections are the foundation of good brake maintenance. It’s smart to have your brakes checked at least once a year. During an inspection, a technician will examine the pads, rotors, calipers, and brake lines for wear or damage. Catching small issues early—like thinning brake pads or an emerging fluid leak—can prevent bigger, more expensive problems later on. Regular checkups also help ensure that your braking system remains responsive and safe. Replace Brake Pads Before They Wear Out Completely Brake pads are designed to wear down gradually, but driving with pads that are too thin can cause damage to your rotors and reduce stopping power. If you hear squealing or grinding when braking, it’s likely time for replacement. Investing in timely pad replacement can save you from costly repairs. Keep Brake Fluid Fresh and Full Brake fluid transfers the pressure from your foot on the pedal to the brake components. Over time, brake fluid can absorb moisture, reducing its effectiveness and leading to corrosion in the system. Check your brake fluid level regularly and have it flushed according to your vehicle manufacturer’s recommendations. Clean, properly filled brake fluid enables consistent performance and a firm brake pedal feel. Avoid Aggressive Driving Habits Frequent hard braking, tailgating, and high-speed stops generate excessive heat and wear on your brake components. Adopting smoother driving habits—such as maintaining a safe following distance and gradually slowing down—can extend the life of your brakes. Address Any Brake Warning Signs Immediately If your brakes start making unusual noises, feel spongy, vibrate when applied, or cause your car to pull to one side, don’t ignore these warning signs. These symptoms can indicate worn parts, low fluid, or other problems that require professional attention. Promptly addressing brake issues helps ensure your vehicle remains safe. Brake Service in Novato, CA For expert brake service in Novato and the surrounding area, contact Novato Auto Service at  415-598-1488  . Feel free to give us a call to make an appointment!
By Novato Auto Service October 1, 2025
Our team at Novato Auto Service strives to exceed our customers’ expectations by providing expert auto repair and maintenance at fair rates, while consistently finishing the work in a timely fashion. Our local mechanics take great pride in completing every job to the highest standards with the goal of earning our customers’ total satisfaction. And we’re grateful when our customers offer feedback about our work. Here’s a look at some of our latest customer reviews. “I have taken my car here for years, and will continue to. Scott always takes care of me. Great communication, timely and thorough.” — Dana R. “Nothing but great things to say about Scott and his team over at Novato Auto Service. I had been coming to them for a few years and he has helped keep my truck in tip top shape. Incredible mechanic, honest, flexible, fairly priced and goes above and beyond doing incredible work. He has done a little bit of everything for my truck and it has never run better. Highly recommend if you are looking for a fair, reliable and honest mechanic who can fix just about anything in the Novato or Marin area. Beats the dealership by a long shot.” — Shane M. “Scott and his team delivered. I have a 1 ton truck that needed major maintenance. They got it all done in a day, communicated with me during the process and did an excellent job. Highly recommend these guys!” — Stephen C. “I really appreciate this family business. They really take care with great service, advice before they perform a service, and reasonable estimates. I've taken my older cars to them for years and have always known I'll come back to them.” — Marcella K. “All professional yet so friendly.” — Christine M. Auto Repair in Novato, CA When you need auto repair in Novato, CA and the surrounding area, contact Novato Auto Service at  415-598-1488  . At our local auto shop, we can expertly address your vehicle’s repair and maintenance needs. Feel free to give us a call to schedule an appointment !
By Novato Auto Service September 4, 2025
Few car issues are as stressful as seeing your temperature gauge climb into the danger zone or spotting steam pouring out from under the hood. An overheating engine can cause severe damage if ignored, and the problem can escalate quickly. Understanding the most common reasons cars overheat can help you stay on top of maintenance and address issues before they lead to costlier repairs. At Novato Auto Service, we provide expert cooling system repair in the greater Novato, CA area. Here are four common causes of overheating. Cooling System Leaks Leaks are among the most common culprits of overheating. A cracked radiator, worn hose, or faulty water pump are issues that can allow coolant to escape, leaving your system unable to maintain proper fluid levels. Even small leaks can cause big problems over time. If you notice puddles of coolant under your car, it’s a strong indication of a leak that needs immediate repair. Malfunctioning Thermostat The thermostat regulates how coolant flows through your engine. When it works correctly, it ensures the engine warms up efficiently and then maintains an optimal operating temperature. But if the thermostat becomes stuck closed, coolant won’t circulate properly, leading to overheating. A faulty thermostat is a relatively inexpensive fix that can save your engine from major damage. Broken Water Pump The water pump circulates coolant throughout the engine and radiator. If it fails, coolant won’t move efficiently, and overheating can quickly result. Because the water pump is crucial for proper cooling, any signs of failure such as leaks, whining noises, or engine temperature spikes should be addressed immediately. Blocked Radiator Your radiator is designed to dissipate heat, but if it becomes clogged with debris, rust, or sediment buildup, it can’t do its job effectively. Without efficient heat exchange, your engine temperature can rise rapidly, leading to overheating. Regular inspections and flushing the cooling system at recommended intervals help keep your radiator in good condition. Cooling System Repair in Novato, CA For expert auto repair in Novato and the surrounding area, contact Novato Auto Service at  415-598-1488  . Feel free to give us a call to make an appointment!
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