Check Engine Light Trouble? Five Common Sensor Issues

As a vehicle owner, it’s stressful to see a ‘check engine’ light staring back at you from the driver display. While industry-wide advancements make it easier to know when something is wrong with our vehicles, the ‘check engine’ light is still a mystery that requires a trusted and experienced mechanic—like those at our auto repair shop in Loganville—to diagnose and resolve. But why is this the case, and what are the most common issues behind that pesky light?

A ‘check engine’ light is often associated with a faulty sensor in your vehicle. Cars, trucks, and SUVs are incredibly complex, from their powertrains to their suspensions and drivetrains. These systems rely on various sensors to monitor your vehicle’s performance as you run around Loganville and beyond the city limits, from tire pressure to speed, oxygen levels, and operating temperature. When one of these sensors fails, your vehicle doesn’t have the information it needs to run effectively, efficiently, or—in some cases—safely.

As the leading auto repair shop in Loganville, we’re here to demystify the ‘check engine’ light and the many sensors your vehicle relies on whenever you’re behind the wheel. We’ll look at the various types of sensors and what they do, also noting what to look for when a sensor fails.

#1. Oxygen Sensor

Your internal combustion engine relies on a mixture of air and fuel to create the miniature explosions your vehicle needs to operate. This mixture of oxygen and fuel must be perfect for your engine to perform optimally, which is why the oxygen sensor is such a critical component; it measures the amount of oxygen in the exhaust, comparing it to the oxygen levels around the engine to determine if the air-fuel mixture is rich or lean. Depending on the result, the sensor determines if the engine needs more or less oxygen.

Signs of Failure

Beyond a ‘check engine’ light, a faulty oxygen sensor is recognizable in several ways. For example, you may see black smoke from the exhaust or an odor that resembles rotten eggs. The engine itself may also surge or jerk when idling, or you may notice a sudden decrease in your average fuel economy that forces you to make more frequent stops at the pump. In any case, remedying a faulty oxygen sensor should be done immediately because, if ignored, it can cause more extensive and expensive problems.

#2. Mass Air Flow Sensor

While oxygen sensors monitor the oxygen levels in the exhaust, the mass air flow sensor monitors the amount of oxygen that reaches the engine. Commonly abbreviated MAF, the Mass Air Flow sensor is located in the combustion chamber; its sole job is to measure the density and volume of the oxygen flowing into the engine, determining how much fuel needs to be injected to optimize your vehicle’s performance and efficiency.

Signs of Failure

A failing Mass Air Flow sensor presents like a bad oxygen sensor, making it impossible to diagnose without the help of our technicians. The engine may suddenly jerk as you accelerate or sound rough when idling. Additionally, you may notice black smoke coming from the tailpipe or spend more money on fuel since the sensor isn’t effectively telling the fuel injection system how much fuel the engine needs to balance its oxygen levels.

#3. Tire Pressure Sensor

Decades ago, monitoring the pressure in your tires required getting out of your vehicle and measuring the pressure in each tire with a handheld gauge. Today, vehicles have integrated tire pressure monitoring systems that alert us to low air pressure in each tire. It’s a convenience that’s integral to our safety behind the wheel and how well and efficiently our vehicles operate. Tires that aren’t correctly inflated pose a threat to our safety, minimizing our traction, hindering our stopping power, and putting us at risk of having a blowout.

Signs of Failure

A faulty tire pressure sensor can be annoying because, in many instances, it constantly alerts you to low air pressure when you know your tires are properly inflated. In other instances, a bad tire pressure sensor may be the result of a dying vehicle battery or corrosion, which is caused by debris buildup around the sensor. You can also recognize a faulty tire pressure sensor by using a traditional tire gauge and comparing the results with the system, filling and releasing the air in your tires as part of the test. For us, diagnosing the issue is as simple as using our cutting-edge diagnostic equipment to determine the cause and the best solution.

#4. Temperature Sensor

Your engine relies on many moving parts working together, with your oil lubricating, cleaning, and cooling these components as they move. However, even with the oil reducing the heat and friction, there’s still an excessive amount of heat under the hood, and too much can be detrimental to your engine’s performance, leading to potential failure and costly repairs. Fortunately, your vehicle’s temperature sensor mitigates this concern by constantly monitoring the engine’s temperature to ensure ideal operating conditions. It’s responsible for measuring this temperature and your coolant levels, and it can alert you to issues with the cooling system, like the radiator or fan.

Signs of Failure

A bad temperature sensor—commonly known as a coolant temperature sensor—presents in several ways. For example, you may notice the temperature gauge on the driver dashboard fluctuates at the extremes when it typically stays in one place. A faulty temperature sensor can also make it difficult to start the engine or cause problems with the transmission, and it commonly shows up as a ‘check engine’ light or—like the oxygen and Mass Air Flow sensors—may cause billowing black smoke from your tailpipe.

#5. Engine Speed Sensor

For many of us, driving is nothing more than getting behind the wheel, starting the ignition, and navigating our routes. However, what’s happening behind the scenes is remarkably intricate and perfectly choreographed to ensure your vehicle runs its best. The engine speed sensor plays a prominent role in that choreography by monitoring the position and speed of the crankshaft and relaying that data to the Electronic Control Unit or the brains of the entire system. This data tells the ECU when to inject the fuel and activate the spark plugs so that efficiency is at its highest.

Signs of Failure

A faulty engine speed sensor can dramatically impact your vehicle’s performance and efficiency, making it another essential component. When this sensor fails, you may notice the reading on the speedometer doesn’t seem right or that the cruise control no longer works. Sometimes, a malfunctioning sensor can affect the transmission, causing hard shifts or limiting the available gears.

Knowing Who to Trust

Your vehicle relies on dozens of sensors to gather the necessary data to operate efficiently and effectively as you navigate life in and around Loganville. So, the question is, who can you trust to diagnose and resolve faulty sensors? As the leading auto repair shop in Loganville, you can rest easy knowing your car, truck, or SUV is in trusted hands with our team. From our state-of-the-art facility to the talents of our factory-trained and certified technicians, we promise nothing short of extraordinary when you bring your vehicle in for service and repair.