Is Check Engine Light Serious?

A Check Engine Light.

Is check engine light serious?

If you’re driving along and your check engine light suddenly comes on, you will probably worry about the seriousness of the problem. What can create stress is not knowing what’s going on with your vehicle is that when the light comes on, it could mean different things. In general, it just signifies a malfunction. The malfunction could be something as minor as a faulty gas cap or as serious as misfiring engine.

To determine the seriousness of the problem, you’ll need to take the vehicle to a repair shop for a check engine light diagnosis. For the most accurate diagnostic in Lombard and Wheaton, IL, bring your car to J1 Auto Repair. We offer a full range of reliable repair and maintenance services. Call 630-932-4427 to schedule a service appointment.

What could cause the check engine light to come on?

When the check engine light comes on, it could mean various things for your vehicle. Below are  common reasons the check engine light may come on.

  • A missing or loose gas cap: The car’s computer is sensing a pressure change in the fuel delivery system, which will cause the light to come on. Tightening the gas cap or replacing it will normally cause the light to turn off.
  • A faulty oxygen or O2 sensor: This sensor measures the level of unburnt oxygen in the car’s exhaust system. If the oxygen sensor isn’t repaired it will cause your vehicle to burn more fuel and can damage components like spark plugs and the catalytic converter.
  • Catalytic converter has failed: The catalytic converter processes carbon monoxide into carbon dioxide and is essential to the vehicle’s emissions. 
  • Spark plug or ignition coil issues: Ignition coils generate the electricity for the spark plugs to ignite the fuel. Worn or dirty spark plugs can cause the engine to misfire and bad spark plug wires can cause a drop in engine performance and lower gas mileage.
  • Problem with mass airflow sensor: This part monitors the amount of air that gets into the engine, and a malfunction can cause a rough idle or problems with starting, as well as lower gas mileage or even stalling. 
  • Aftermarket alarm problems: An alarm that’s installed aftermarket can create problems including turning on the engine light if improperly installed.

Where to get check engine light diagnosis

When the check engine light comes on, you’ll need to have a diagnostic run to find out what is wrong. There are several options you can take to get the diagnostic done. You can purchase a diagnostic tool yourself and scan the codes yourself. You can also go to an auto parts store like AutoZone, but these diagnostic tests aren’t always comprehensive, and further tests may need to be made. You can also go to your dealership or to a professional repair shop like J1 Auto Repair, where you can be assured the tests are comprehensive, and you can rely on any repairs that need to be made.

One area where there are no warning lights to show you have problems is your plumbing. Sometimes plumbing repairs come as a surprise, and you’ll want a reliable plumber for emergency plumbing repair.

Can you diagnose a car without check engine light?

If you’re having problems with your car like a rough idle or are experiencing engine misfires, but your check engine light doesn’t come on, it is possible to run a diagnostic to find out what the problem is. A skilled mechanic can download the error codes that are stored in your car’s computer system, and make tests and checks from there to diagnose the issue. From there, they can recommend repairs. Never hesitate to bring in a vehicle for a diagnostic, even if no warning lights have appeared on the dash. 

Can check engine light turn itself off?

Most of the time if a warning light comes on, the problem has to be remedied before the light will go off. Occasionally, the light will go off on its own. The car’s computer may adjust briefly, especially after extended highway driving, but after a short time, the light will probably come on again. Some issues like a malfunctioning catalytic converter may cause the light to flash or flicker, and it may shut off briefly. In other instances, the light may turn off and on as you drive, but will only stay off permanently once the repair is made.

How long does a check engine light diagnosis take

The time it takes to run a diagnostic can vary. Some of the free diagnostics provided by auto parts stores may just take a few minutes. Generally, these tests just find error codes, but may not be comprehensive enough to fully diagnose the problem. A test at a repair shop like will be more comprehensive J1 Auto Repair. These tests can take anywhere from a few minutes to several hours, depending on the situation. 

How much is check engine light diagnosis?

While you can get free diagnostics performed at auto parts stores or you can do it yourself by purchasing a scanner for about $60, you’ll get a comprehensive diagnostic from professionals at auto repair shops and dealerships. These diagnostics will cost on average anywhere between $88 and $111. Some repair shops may offer diagnostics for free or as part of other services. The cost may also vary depending on the make and model of your vehicle and your location. Check with your local mechanic to find out prices in your area.

Will check engine light fail emissions test

In Illinois, your vehicle will not pass an emissions test. In fact, if your engine light is on when you pull in to have the vehicle inspected, the vehicle will not be inspected. Repairs must be made before the vehicle will be inspected. Even if repairs are made, the trouble codes must not appear or the vehicle may fail the inspection.

A Mechanic Tests an Engine.

Check engine light diagnostic near me

If your check engine light in Lombard and Wheaton, IL comes on, don’t hesitate to get the vehicle checked to avoid further problems. The reliable professionals for diagnostics and repairs are those at J1 Auto Repair. Give us a call at 630-932-4427 to set up a service appointment.