Check Engine Light Diagnostics and Services


Your car's dashboard has quite a few informational and warning lights, but perhaps the most alarming of them is the check engine light. Because it can mean such a wide range of things, people tend to assume the worst when they see it come on. Don't panic, though! The light definitely indicates that your car needs some attention, but it doesn't always mean you have an expensive repair on the horizon.
At SJM Autowerks, we're here to help you figure out what your check engine light means and help you get back on the road quickly and with confidence. Some of the models we specialize in include:

  • Volkswagen
  • BMW
  • Volvo
  • Mercedes
  • Audi
  • Mini
  • Jaguar
  • Porsche
  • Land Rover

Why Does Your Check Engine Light Come On?


The check engine light is part of your on-board diagnostics (or OBD) system. When the system detects something wrong with your engine or emissions system, the computer triggers the light. It can be something as simple as a loose gas cap, or as complex as an engine misfire. A steady light usually indicates a less urgent issue, but one that still needs attention. It might be related to emissions or a minor problem with the engine. Alternatively, a flashing check engine light means something more serious has been detected, and should be checked as soon as possible.

Some of the most common reasons your check engine light might come on includes:

  • A loose or faulty gas cap: Your fuel system requires a certain pressure to operate, and if the gas cap isn't closed or sealing, it can't maintain that pressure. You can try tightening or replacing the gas cap to see if that resolves the issue.
  • Failing oxygen sensor: The oxygen sensor helps determine the fuel mixture in your car by monitoring the amount of oxygen in the exhaust. If this sensor is damaged, it can really do a number on your wallet at the gas pump.
  • Bad catalytic converter: Your car's catalytic converter helps prevent harmful emissions by changing the toxic gasses into less harmful substances. If yours is failing, it can cause poor engine performance and cause the check engine light.
  • Mass airflow sensor: The mass airflow sensor, or MAF, is the counterpoint to the oxygen sensor — it measures the amount of air coming into the engine so that the right amount of fuel can be injected. Rough idling, poor acceleration, and decreased fuel efficiency can all be symptoms of a failing MAF sensor.
  • Spark plug or ignition coil issues: Worn or damaged spark plugs may cause your engine to misfire, while a failing ignition coil can do the same in addition to rough idling and poor engine performance.
  • EGR Malfunction: The EGR, or exhaust gas recirculation valve, is another important part of your exhaust system that can cause a check engine light if it starts to go bad.

Why Get A Professional Diagnosis?


While you can get your code read many places, or even buy an OBD scanner yourself, interpreting those codes accurately isn't as easy as it seems. At SJM Autowerks, we have certified technicians ready to help with advanced diagnostic tools that can pinpoint your car's problems.
When you see your check engine light come on, it's important to act quickly, as some problems can cause a domino effect if left unattended. At SJM Autowerks, we don't just identify the problem — we fix it. Whether that means replacing damaged components or doing a major engine repair, we're here to help ensure your car gets running smoothly again.

Check Engine Light FAQs


Can I keep driving with the check engine light on?

If the check engine light is steady and you don't notice any changes in your car's performance, you are likely okay to drive for a short while. However, you should still get it checked as soon as possible to prevent further damage. If the light is flashing, stop driving and get your vehicle to a service center immediately.

Can I reset the light myself?

While there are ways to reset the light, doing so does not solve the underlying problem. It is best to address the issue before resetting the light to ensure your car runs properly and does not suffer from further damage.

Will the check engine light ever turn off on its own?

In some cases, the light may turn off after the issue is addressed, especially if it is something simple like a loose gas cap. If your light remains on after trying some easy fixes, we recommend bringing it in for service.

At AJM Autowerks, we specialize in diagnosing and repairing the problems that cause your check engine light to come on, from minor fixes to bigger repairs. Don't ignore the light — doing so can cost you much more in the end. Schedule an appointment with our skilled service technicians today, and we'll make sure your car is in top shape for you to get back on the road.

SJM Autowerks is committed to ensuring effective communication and digital accessibility to all users. We are continually improving the user experience for everyone, and apply the relevant accessibility standards to achieve these goals. We welcome your feedback. Please call SJM Autowerks (815) 477-9735 if you have any issues in accessing any area of our website.