Ask just about any driver about one thing they fear seeing inside their vehicle and they'll say it's the Check Engine light coming on. You know, that little light on your instrument panel that is in the shape of a vehicle engine, often accompanied by the words Check, Check Engine, Check Engine Service, or Service Engine Soon.

There are so many different reasons that light shows up, from something as simple as a loose gas cap to a more serious problem that requires immediate attention. 

The Check Engine light comes on because a component of your vehicle's onboard diagnostics system is telling you something isn't operating normally. Your vehicle has a lot of sensors built in, all tied together by computers.  When the sensors are showing that things somewhere aren't functioning the way they should be, they alert the vehicle's diagnostic computers and tell you something's amiss.

The simple rule is if the Check Engine light is on steadily, it's something you should have checked soon but it's not urgent.  If it's flashing or has turned red or orange instead of yellow, get your vehicle checked out as soon as possible.  If you don't, you may be facing some costly repairs.

Here are a few problem areas that may trigger your Check Engine Light. 

• Something's wrong with the emissions equipment.  Maybe too much fuel is getting into the catalytic converter, or the exhaust gas recirculation system isn't working right.  Because some of these components are expensive to replace, it's worthwhile to have a technician look at your vehicle sooner rather than later.
• Your ignition system isn't working right.  That means spark plugs, coils, and wires.  If your engine is misfiring, that could translate into an illuminated Check Engine light.
• The transmission isn't behaving the way it should.  The transmission works in tandem with the engine, so if a sensor sees something wrong there, it will tell the vehicle to turn on the Check Engine light.

As you can see, there are many things that can cause the light to come on, and when it does, it really is a good idea to find out why.  When you bring your vehicle in, we have an electronic device that can read a code or multiple codes stored in your vehicle's computers.  That will provide the technician with clues pointing to the cause of the trouble and helps pinpoint where that trouble is. 

Tuffy Chicago (Diversey Pkwy)
1400 West Diversey Pkwy
Chicago, Illinois 60614
773-929-3622