1. Oxygen Sensor Issues

An oxygen sensor failure is more than just an inconvenience. It’s a direct hit to your engine’s performance and fuel efficiency. This small component measures the oxygen levels in your exhaust, helping your car adjust its air-to-fuel ratio. When it fails, your car runs rich, burns too much fuel, and may even damage your catalytic converter. Vehicles like the 2013-2019 Toyota Corolla and 2012-2017 Honda Accord frequently experience sensor failures after about 90,000 miles.

At Precision Auto Care, we start with a full diagnostic scan to pinpoint the faulty sensor. With some cars housing up to four sensors, accuracy is critical. Once identified, we swap it out with a high-quality replacement, recalibrate your system, and restore your car’s efficiency. A failing oxygen sensor doesn’t just hurt your wallet at the pump—it can lead to bigger problems down the line.

2. Catalytic Converter Failures

Your catalytic converter is the unsung hero of your car’s emissions system. It converts harmful gases into less toxic emissions. But when it’s clogged, overheated, or damaged, it doesn’t just fail—it can take your entire engine with it. Cars like the 2011-2016 Ford Escape and 2012-2018 Nissan Altima are prone to catalytic converter issues, especially if oil consumption is high or misfires are ignored.

We don’t just replace parts—we find the root cause. At Precision Auto Care, our team checks for upstream problems, like bad spark plugs or oxygen sensors, that may have caused the failure. If replacement is needed, we install a direct-fit catalytic converter designed to meet California’s strict emissions standards. It’s not just about fixing what’s broken—it’s about making sure it doesn’t happen again.

3. Mass Airflow Sensor Problems

Your mass airflow (MAF) sensor is your car’s breath of fresh air—literally. It measures incoming air and tells your engine how much fuel to add for combustion. A dirty or failing MAF sensor leads to rough idling, poor acceleration, and a dive in fuel efficiency. Models like the 2014-2020 Subaru Forester and 2013-2018 Chevrolet Malibu often see MAF sensor issues, especially if air filters haven’t been replaced on schedule.

Our approach starts simple: inspect and clean. Often, dirt and debris are the culprits, coating the sensor and skewing its readings. If cleaning isn’t enough, we replace it with a manufacturer-approved part. To finish, we install a new air filter and test your car’s response. A clean airflow system means a smooth ride—and fewer trips to the pump.

4. Gas Cap Troubles

It’s almost laughable—a gas cap causing a check engine light? But it happens more often than you’d think. A loose, cracked, or missing gas cap can trigger your car’s emissions system to detect a fuel vapor leak. Newer models, like the 2020-2022 Toyota Camry and Honda CR-V, are particularly sensitive to gas cap issues.

The fix? Quick and easy. We inspect the cap, checking for cracks or poor sealing. If it’s loose, we tighten it. If it’s damaged, we replace it with an OEM part. Sometimes, it’s the simplest fixes that save you the most stress.

5. Ignition Coil and Spark Plug Failures

Your ignition coil and spark plugs are the lifeblood of your engine. They ignite the air-fuel mixture that powers your car. When they fail, you’ll feel it—misfires, sluggish acceleration, and an engine that stumbles instead of purring. High-mileage cars like the 2008-2015 Honda Civic and 2010-2016 Chevrolet Silverado are notorious for these issues.

At Precision Auto Care, we identify the misfiring cylinder and inspect the ignition system. Faulty spark plugs are swapped for platinum or iridium replacements, while bad coils are replaced with parts that meet or exceed OEM standards. After the repair, we perform a system test to confirm your engine is firing on all cylinders. Smooth, reliable, and ready for the road.

6. EVAP System Leaks

Your EVAP (evaporative emissions control) system prevents fuel vapors from escaping into the air. Over time, its components—hoses, valves, seals—can crack or fail, triggering the check engine light. Older vehicles, like the 2007-2013 Jeep Grand Cherokee and 2010-2015 Toyota Prius, often suffer from EVAP leaks due to wear and tear.

Fixing EVAP leaks requires precision. We use smoke machines to detect tiny leaks invisible to the eye. Once found, we repair or replace the faulty component. Whether it’s a cracked hose or a bad purge valve, we seal the system tight. California’s emissions standards leave no room for error—and neither do we.

7. Exhaust Gas Recirculation (EGR) Valve Failure

The EGR valve reduces nitrogen oxide emissions, keeping your car compliant with environmental standards. But when it clogs with carbon deposits, it’s like trying to breathe through a straw. Symptoms include rough idling, stalling, and poor fuel efficiency. Trucks like the 2011-2018 Ram 1500 and 2010-2017 Ford F-150 often experience EGR valve issues as mileage climbs.

Our team removes the valve, cleans it thoroughly, and inspects related components for buildup. If cleaning doesn’t restore function, we replace the valve with a manufacturer-approved part. After reinstalling and testing, your engine runs smoother, cleaner, and stronger.

Ignoring your check engine light isn’t an option. Small problems grow into big repairs faster than you think. At Precision Auto Care in San Leandro, we diagnose, fix, and prevent the seven most common issues behind your warning light. Whether you’re local or coming from nearby cities like Oakland or Castro Valley, we’re here to keep your car in top shape. Don’t wait—let’s fix that light today.