Demystifying your Car Warning Lights

Car warning lights -- they are a common plague but here are answers

Car warning lights

Sometime during your life behind the wheel of your car, you’re going to see your car warning lights come on, illuminating words like “Check Engine” or “Oil Pressure.” The wildcard question: How will you react? Will you immediately pull to the side of the road and start sobbing? Or will you continue on your way as if nothing has happened?

Part of the problem is the cryptic nature of the messages. For example, if you heed the advice to check your engine, you will likely peer under the hood and determine that the engine is still there — and that it looks pretty much like it did when you saw it before, assuming you have seen it before. Similarly, if you see the words “Oil Pressure,” you may immediately think that you must somehow add oil to the pressure — whatever and wherever that is — and that could be a problem. It was Franklin Delano Roosevelt who famously said, “The only thing we have to fear is fear itself.” Sadly, this is not true when it comes to your car.

Car warning lights go on for a reason…really

“Warning lights are there for a reason: to let us know something is wrong with our car,” said John Nielsen, AAA managing director, automotive engineering and repair. “In some cases, ignoring a warning light can quickly result in catastrophic damage to your car’s engine, so it’s important to know what each light means and what you should do if it comes on while driving.”

Sure, easy for him to say. He’s a font of automotive knowledge. What about the typical driver in the typical car on the typical freeway in the typical city? Well, good news has arrived: Deciphering car warning lights doesn’t have to be as arcane as reading tea leaves. Here, with the help of AAA’s experts, are some quick facts about three very important warning lights you may someday see:

Oil Pressure Light
The oil pressure light — which usually appears as a symbol that resembles an oil can or as the word “OIL” — illuminates when there is a major drop in engine oil pressure. This is serious, folks. Oil lubricates the vital portions of your engine, and if that lubrication isn’t happening, your engine can quickly grind itself into rubble. AAA advises to pull off the road immediately, shut off the engine and call for assistance. Do not attempt to drive the vehicle any further than is absolutely necessary. Doing so will significantly increase the extent of any engine damage, turning what might be a minor repair into a complete engine replacement. Big ka-ching!

Engine Temperature Light
The engine temperature light — which usually appears as a thermometer symbol or as the word “TEMP” — comes on when the engine temperature has exceeded the level the manufacturer considers to be the safe maximum. High engine temperatures can cause major engine damage and even catastrophic failure, but you do have a little more time to deal with the situation than with the oil pressure warning. If there are any signs of a cooling system leak — such as steam or liquid coolant coming from under the hood or trailing off behind your vehicle — pull off the road at the earliest and safest opportunity, shut off the engine and call for assistance. Coming into contact with boiling coolant can cause severe burns, so be careful when opening the hood in the presence of steam, and never remove the radiator cap when the engine is hot.

In the absence of obvious symptoms like that, though, the overheating may have resulted from a temporary overload of the cooling system. This can sometimes occur in hot weather when the vehicle is heavily loaded or pulling a trailer. To help lower the engine temperature: Reduce vehicle speed, turn off the air conditioning, roll down the windows, set the heater to the full hot position and operate the heater fan on its highest setting. The heater is actually a second radiator that can provide additional cooling for the engine. In this mode, you can likely make it to the next service station, where a professional mechanic can assess your situation.

Charging System Light
The charging system light — which usually appears as a battery symbol or the word “ALT” or “GEN” — illuminates when the vehicle electrical system is no longer being supplied with power by the alternator. Charging system failure rarely results in serious mechanical damage, and of the “big three” car warning lights, this one gives you the greatest latitude to take action. First, shut down all unnecessary electrical loads (radio, heater, air conditioning, etc.), then drive the vehicle to a repair facility for further inspection. Generally, you will have at least 15 minutes of daylight driving time (non-headlight use) before the battery voltage drops to the point where the ignition system will no longer function and the engine will quit.

About Tom Ripley 54 Articles
Born in Boston, Tom Ripley has been writing about the automotive industry and the human condition for more than a decade. He's a frequent traveller but nominally resides in Villeperce, France.