What the Dashboard Warning Lights Mean in Your Car
CR's experts decode oil pressure, coolant temperature, check engine, tire pressure, and traction control warnings
Every car has its own language of light-up hieroglyphics on the dashboard. They’re your car’s way of asking for help. But those lights are not always easy to interpret.
What it means: Typically red, these lights mean the engine can’t lubricate or cool itself adequately. Left unchecked, either problem will cause the engine to overheat. The oil pressure/level light typically looks like an old-fashioned oil dropper bottle—like what the Tin Man in "The Wizard of Oz" carries. The coolant light is supposed to look like a thermometer in liquid.
What to do if it lights up: Either one indicates a serious problem that can cause irreversible engine damage. Pull over and turn the engine off as soon as it’s safe and have the car towed to a mechanic.
What it means: This light, which usually looks like a 1960s-vintage V8 with a carburetor on top, means there’s an issue with the emissions control system—the components that reduce the pollution created as the engine burns fuel. Any number of problems can cause an abnormal reading; for example, one of the many sensors, the wiring, or some hoses may have failed.
What to do if it lights up: If this light is flashing or the car is making strange noises, pull over and get towed to a repair shop. If the light is on but the car seems okay, drive yourself to a shop soon—a hidden problem might be damaging the catalytic converter.
What it means: Low pressure in one or more of the tires will cause the tire pressure monitoring system (TPMS) to illuminate a warning light. The problem could be from a puncture, a slow leak, or cold weather—all of which affect tire wear, handling, and safety.
What to do if it lights up: Driving for more than a mile or two on a tire with very low pressure is dangerous and can ruin the tire. Head to a gas station as soon as possible—most have air compressors with built-in tire pressure gauges. Fill the tire(s) to the pressure shown on the sticker located inside the driver’s door. If the light comes on again, have a tire shop check for leaks. (See the best tire retailers.)
What it means: When a tire that’s getting power from the engine loses grip, the traction control system (TCS) activates and this light flashes. This usually happens because the car has detected that one wheel is spinning significantly faster than the others, so it limits power and uses the brakes to maintain grip. This improves overall traction and prevents dangerous skidding.
What to do if it lights up: If it flashes briefly, don’t panic—that just means the TCS was active. If the light is on continuously, there’s a problem with the system or it is turned off. It can be dangerous to drive without TCS, so take the car to a mechanic as soon as possible.
Editor’s Note: This article also appeared in the May/June 2025 issue of Consumer Reports magazine.
