While not all warning lights indicate disastrous consequences are about to occur, no illuminated warning indicator should ever be ignored. AAA encourages motorists to check their owner’s manual for a detailed explanation of all of the warning lights in their vehicle. Some of the more common indicators found in vehicles are described below.

Oil Pressure Light

The oil pressure light (usually an oil can symbol or the word “OIL”) illuminates when there is a drop in engine oil pressure. Of all the warning lights, the oil pressure light indicates the greatest potential for serious mechanical damage. Unfortunately, it also allows you the shortest time in which to take action.

If the oil pressure warning light comes on and stays on, 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.

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Engine Temperature Light

The engine temperature light (usually a thermometer symbol or the word “TEMP”) comes on when the engine temperature has exceeded the safe maximum. If the increase in temperature is not stopped, major engine damage or catastrophic failure will result. While the engine temperature light also indicates the potential for severe engine damage, it normally gives you a little more time to take action before that occurs.

If there are any signs of a cooling system leak, such as steam or liquid coolant coming from under the hood, pull off the road at the earliest safe opportunity, shut off the engine, and call AAA for assistance. 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.

Charging System Light

The charging system light (usually a battery symbol or the word “ALT” or “GEN”) illuminates when the vehicle electrical system is no longer being supplied power by the alternator. Charging system failure rarely results in serious mechanical damage, and of the “big three” warning lights, this one gives you the greatest amount of time to take appropriate action.

If the charging system light comes on: 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 before the battery voltage drops to the point where the ignition system will no longer function and the engine will quit.

Check Engine Light

The check engine light (usually an engine symbol with the words “CHECK ENGINE SOON”) comes on when there is a problem affecting the vehicle’s exhaust emissions. When the check engine light is on, the vehicle may display drive ability symptoms and the fuel economy will likely decrease.

If the check engine light comes on and stays on, make an appointment with an auto repair shop to have the problem checked in the near future. However, if the check engine light begins flashing repeatedly, the catalytic converter is overheating. Should this occur, drive the vehicle to a repair shop immediately for further diagnosis. Disregarding a flashing check engine light could start a fire, destroy the catalytic converter and result in necessary repairs that could easily exceed $1,000.

Tire Pressure Light

The tire pressure monitoring system light (usually a tire cross section symbol with an exclamation point) comes on when one or more tires are significantly underinflated. This may be the result of gradual pressure leakage over time, or an object that has punctured a tire.
If the tire pressure monitoring system displays individual tire pressures, check the dash display. If the pressures are all within a few pounds of one another, the warning is probably from gradual leakage over time; check and adjust the tire pressures as soon as possible. If one pressure is significantly lower than the others, a puncture is likely. A severely deflated tire will also affect handling and may cause the vehicle to drift to one side. Pull off the road at the first available safe location and call for assistance.

Where the tire pressure monitoring system does not display individual tire pressures, pull off the road at the first available safe location and check the tire pressures. If you don’t have a pressure gauge, listen for leaks, feel for objects in the tire treads, and look for a tire that is obviously low on air. If a problem is apparent, call for assistance. Otherwise, drive at reduced speed to the nearest gas station or repair facility to have the tires inspected and the pressures adjusted.