October 21, 2020
Dashboard indicator lights look straightforward enough, but what does it mean if one is flashing instead of solid?
Why are some red and others yellow? And how are you supposed to “check engine,” anyway? We look at how to interpret what your indicators are telling you.
Dashboard warning indicators come in 2 main colors: red and yellow. (Some cars use orange instead of yellow.) It's a small but important detail.
Red lights indicate urgent problems that mean the driver should stop driving as soon as possible. If you're not in a safe place to stop, such as a busy highway, it's OK to drive until you reach a safe stopping point. But continuing to drive for long periods with red dashboard lights can lead to serious and potentially irreparable mechanical damage.
Yellow lights indicate problems that require attention but don't pose immediate risk of damage. While these issues don't require you to stop driving ASAP, they should still be checked out quickly.
Not all lights are the same color in every car; for example, in some cars the air bag light is yellow, while in others it's red.
Perhaps the most notorious dashboard indicator, this yellow light appears as an outline of an engine, the words "Check Engine," or a combination. It's usually triggered by a fault in the emissions system, which includes a broad number of issues from bad spark plugs and faulty catalytic converters all the way to a gas cap not being screwed on correctly.
Because the Check Engine light is vague, it can be tempting to ignore it. But even if the light isn't accompanied by an obvious problem, the underlying issue may lead to premature engine wear, worse gas mileage, increased emissions, or all 3. As with any yellow dashboard light, take your car to a mechanic at the first opportunity.
STEADY: Most issues will prompt a steady Check Engine light, which indicates an issue that needs to be checked out soon but not immediately.
FLASHING: This indicates a more severe issue, such as a cylinder misfire. Don't drive the car any further than necessary to get to a trusted repair facility.
The oil light is red, and for good reason. It indicates the engine isn't getting enough oil to properly lubricate all those moving parts. In many instances it results from an extremely low oil level, and the light may only come on when accelerating or taking tight corners.
Even if the oil light only comes on for a few seconds at a time, continuing to drive can lead to severe damage. Engine parts aren't designed to survive without lubrication, ever. If you see this light at all, stop driving at the earliest safe opportunity and check your oil level. If it's low, either refill it to the proper level or have it towed to a mechanic. If it's not low, or refilling it doesn't turn the light off, have the car towed to a mechanic.
This yellow light usually appears as a tire with an exclamation mark. It indicates that the tire pressure monitoring system (TPMS) wants your attention, for 1 of 2 reasons:
STEADY: If it comes on and stays on, it's indicating that the air pressure in at least 1 tire has dropped at least 25% below the level the TPMS is set to.
FLASHING: If it flashes for a period after starting the car, it's indicating that the TPMS system itself is experiencing a malfunction and should be looked at by a mechanic.
Note that you shouldn't wait for your TPMS light to come on to check your tire pressure—driving on underinflated tires leads to bad fuel economy and uneven tire wear long before the TPMS light comes on. Each pound the tire is underinflated can cause a 2% decrease in fuel economy.
Like the oil light, this red light indicates that your engine is in immediate danger. Pull over and shut off the car at the earliest safe opportunity—minutes can make the difference between a close call and permanent engine damage.
For cars that have an engine temperature gauge, drivers should familiarize themselves with normal operating temperatures. It's better to notice higher-than-normal temperatures and have the engine checked out before this warning light comes on.
This indicator usually only flashes briefly when a wheel begins slipping and the traction control system engages automatically to correct it. This is normal, and the light should go out as soon as the system disengages.
If the light stays solid, or if it flashes when the traction control shouldn't be engaged, that indicates an issue with the system. In some cars, there's a separate light to indicate a traction control problem. It may say "VSC," "TC," or show a car with squiggly lines inside a triangle.
The anti-lock brake system (ABS) indicator comes on to alert you to a fault with the system's sensors or electronic controller. In most cars this light is yellow, though it can be red. In both cases, the fault should be checked out by a mechanic promptly. Anti-lock brakes are an important safety system; you never know when you'll need to make an emergency stop.
This light is red for a few reasons:
PARKING BRAKE: In many cars, it indicates when the parking brake is on to remind the driver to release it before driving. It may stay on during driving if the parking brake isn't 100% disengaged (more common in cars with an actual foot pedal or hand brake), or if something is mechanically wrong with it.
BRAKE SYSTEM FAILURE: If the issue isn't related to the parking brake, that indicates a more serious problem, such as a brake fluid leak or other issue that jeopardizes the brakes' basic functioning. If the brake light comes on while driving and the parking brake is not engaged, you should pull over as soon as safely possible and have your car checked by a mechanic.
Ironically, the battery light generally doesn't indicate that the battery itself is malfunctioning or needs replacement. Rather, it means something is wrong with the system that charges the battery, with the usual culprit being a bad alternator. If the charging issue isn't fixed soon enough, the battery will likely run down, so don't delay having it checked out. Even if the car is already running, it's possible you may only have 20 to 30 minutes of drive time before the battery no longer has enough energy to support basic vehicle functions.
This familiar light usually flashes every time the car is started until the driver buckles up. In some cars, it may also flash if the passengers haven't buckled their seatbelts. The light is red because seatbelts should always be fastened before driving.
If the light remains on after all seatbelts are buckled, the car is still drivable but should be checked out promptly. Issues with the seatbelt sensor can lead the air bag to deploy improperly or not at all in a crash, so it's not something to ignore.
This light is 1 of the most common to see when a car starts up—when everything is working, it comes on and then blinks out after running a self-check. If the self-check finds a malfunction, the light will stay on while driving. In older vehicles, the light may come on because the air bag has passed its "best by" date in age or mileage and needs to be replaced.
In either case, the air bags need to be checked out at a shop soon.
While important dashboard indicators tend to look similar from car to car, there isn't a standard design for all of them, so they can and do vary.
Motorists should familiarize themselves with their car's dashboard lights. A good way to do that is to perform a "bulb check:"
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