Undecided, you consider pulling over or heading several miles down the highway to the next exit where a service station might be found. You’re tempted to keep driving, knowing that your final destination is just 30 minutes away, but you’ve heard horror stories of people who have ruined their engines by not stopping their car promptly following warning light activation.
Fortunately, warning light issues can be identified by checking your owner’s manual to see what they represent. Barring that, AAA offers seven car warning lights you should never ignore and how best to respond:
1. 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.
Some drivers mistakenly believe the oil pressure warning light is an oil level indicator that tells when to add engine oil. This is not true. React quickly to this warning light to avoid costly engine damage.
2. 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.
If there is no evidence of a cooling system leak, the overheating may have resulted from a temporary over load 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 blower motor on its highest setting.
If the warning light does not go out within a couple miles, pull off the road at the first safe opportunity and allow the engine to cool while idling. If the temperature warning light still does not go off after a couple of minutes, shut off the engine and call AAA for assistance.
3. 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.
The charging system light should not be interpreted to mean that the battery needs replacement. A charging system failure may cause the car’s battery to discharge, but that does not automatically mean it needs to be replaced. The complete system should be checked by a trained technician with proper tools and equipment.
4. 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 driveability 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.
5. Brake Light
The brake light (usually a circular symbol with an exclamation point and/or the word “BRAKE”) comes on when there is a loss in brake fluid pressure. However, the brake light can also illuminate to signal the emergency brake is on, so drivers should make sure that is not the case before panicking.
If there is a loss of system pressure, the driver may feel the brake pedal depress farther than usual. When the brake warning light comes on it is extremely important to take the car into a repair facility as soon as possible to have the system thoroughly inspected.
6. Airbag Light
The airbag light (usually a symbol of a seated person with a ball in front of their abdomen) comes on when a problem is detected with the airbag system. When the warning light is on, there is a strong likelihood that one or more of the vehicle airbags have been deactivated and will not deploy if the vehicle becomes involved in a collision. Drivers should make an appointment with a repair facility to have the system inspected as soon as possible.
7. 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 AAA 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 AAA for assistance. Otherwise, drive at reduced speed to the nearest gas station or repair facility to have the tires inspected and the pressures adjusted.