We have all been there - whether you are driving a brand new car just off the lot, or a 1997 tank that's been around the block and has an REM mix tape blaring the entire way. When that yellow wrench-n-engine light pops up on your car's gauge cluster, we can't help but let our an exasperated sigh.  Most of us  have no idea what this simple little light means. We put gas in our car, change the oil every 3,000 miles, and wash it when it's dirty. What else does a car need? Car chow? A chew toy? A play date with a cute  Miata (preferable the topless model)? 

As we learned during our Facebook discussion last week, this little yellow light causes a lot of confusion.   Is it just a conspiracy by auto makers to get you into the dealership for costly service? Is it an attempt by yellow light bulb makers to sell more
yellow lights?  Or is it really something serious to pay attention to?  Most importantly - can we make it to Thanksgiving dinner without breaking down on the side of I-95 in the pouring , chilly  fall rain?    

Believe it or not, that light is a real indicator  that something is not functioning properly within the mechanics of the vehicle. It can be something as simple as  a loose gas cap (as is common with newer vehicles)  or a misfiring cylinder, or even a misaligned plasma warp relay (something that should be fixed if you are going to make it to Andromeda 7 for Thanksgiving this year). The "check engine" light is part of your car's   on board
diagnostics (OBD) system. This computer system monitors the car's internal operation and regulates functions such as RPM, fuel mixture and ignition timing. When the OBD system detects an error that it can't correct on its own, it trips  the check engine light on the dash. At the same time, a trouble code is sent and stored in the vehicle's computer system.   Your mechanic will use a  special  computer scanner  to read the code and determine what has to be fixed. If it's a gas cap that needs to be tightened, the mechanic will be more than happy to twist that sucker closed for a nominal $120 labor fee.   You may want to check your gas cap before heading in to the shop.

What should you  do  if  that annoying, glowing light suddenly appear while you're driving? First, remember not to panic. Breath deeply ensuring optimal oxygen flow to your brain, and allowing for the universal driver's response to the yellow light: ... *sigh!*      Next,  take the glowing wrench seriously. Although it may  be a simple fix,  it could also mean a much needed repair to something that is vital to your vehicles operation like low oil or low coolant levels or a cracked dilithium crystal.  To rule out the easy fixes, check your owners manual to see what your manufacturer suggests.  In general you should check the following easy points before heading to the mechanic: 

* Check that the gas cap is tightly sealed (most cars use the "three click" gas cap, so make sure you hear all three clicks if you have this style cap). 

* Check your engine coolant level, and add some if needed. Our lawyers requested that we remind you not to do this while the car's engine is running, or is hot. The coolant, contrary to it's name, is not cool - it's actually quite hot. 

*  Check your engine air filter and replace it if you see leaves, dust, rodents, or a beaver dam blocking air flow to the engine.  Our lawyers also asked us to remind you not to do this while the vehicle is in motion.  

* Check the air pressure in your tires. While most cars don't connect tire pressure to the check engine light, some do.  Tier pressure, is a good thing to check before a long road trip anyway.  

* Check  your oil level.  Even with iPhones and GPS,  you still need to use the dip stick for this.  Be sure to stare at it thoughtfully so it looks like you know what you are doing.  

* This one could be a little bit more tricky, but if you are comfortable with it go ahead and try:  Check your fuses. A blown out fuse is easy to replace and could save you a trip to the mechanic. 

In the end, if you take care of your car it will take care of you. While I wouldn't recommend cancelling your Thanksgiving road rip, I would start with some of the easy troubleshooting suggestions above.  Then, I would have a mechanic take a look at your earliest convenience.   Some people drive for several thousand miles with that check engine light on, and never have a problem. Maybe their light is caused by the failure of the cruise control system which they rarely use.  Or, it could be caused by a clogged air filter which will leave them stranded on the side of the road in Smallville North Dakota.  Put your road trip in your own hands by paying attention when your car asks for your help.  

Do you have any suggestions about what to do when the check engine light appears? Comment on this topic below!