Common Car Dashboard Symbols and Meanings

There are several reasons your Check Engine warning light may activate. To know where to start with diagnosing the problem, the engine's trouble code(s) must first be read. At O'Reilly Auto Parts, our parts professionals are equipped to scan vehicle Check Engine trouble codes to assist with finding a service solution. If your Check Engine light is on, then visit your local O'Reilly Auto Parts store for Free Check Engine Light testing.

Check Engine Light Resources:
What Causes a Check Engine Light?
What Causes Engine Misfires?
What is Engine Knock?

If your car battery or charging light is on, it indicates a problem with the charging system on your vehicle. Though there is a good chance you will need a replacement battery, in some cases the battery may still test "good" if it is properly recharged. If that is the case, this might be a sign of a bad alternator, damaged or corroded battery cables, or other problems. O'Reilly Auto Parts offers Free Battery Testing and Free Alternator Testing to help you determine which component, if any, needs to be replaced.

Battery and Alternator Resources:
All About Car Batteries
How to Care for Your Car Battery
Why Won’t My Car Start?

When you see an active coolant or temperature light, it's usually an indicator that your engine is overheating, and it's best to stop driving and turn your vehicle off as soon as it is safe to do so. Once the engine has cooled off, check your coolant level to ensure it is filled appropriately. It is also best to look for coolant leaks if the level is lower than it should be, make sure your cooling fan(s) are working, and inspect the radiator hoses and radiator cap to be certain they are holding pressure. It's recommended that you not drive the vehicle until you've repaired an overheating or cooling system issue to prevent any major engine damage, including head gasket failure or warped cylinder heads, a cracked engine block, and more.

Cooling System Resources:
Cooling System Maintenance
What Causes a Car to Overheat?

The transmission warning light usually indicates that your transmission is overheating or low on transmission fluid, but could also illuminate due to a variety of other transmission related issues depending on the types of transmission sensors equipped on your vehicle. Since a transmission issue can cause significant safety and driveability problems, it’s best to not continue driving your vehicle until the transmission has been diagnosed and repaired. This may be as simple as checking the transmission fluid level and condition and adding fluid, or may require a properly-equipped transmission shop to resolve the issue.

Transmission Resources:
How to Check and Fill Transmission Fluid

When your oil pressure light is activated, it can mean low oil levels or failure of an oil system component, including a weak oil pump, clogged oil passages, and more. Check your vehicle's oil dipstick to determine the oil level and condition and look for any leaks. If your oil levels are normal, then you may need to perform more intensive diagnosis, part replacement, or engine service. Driving your vehicle with low oil levels, dirty oil, or poor oil circulation can quickly result in significant engine damage or complete engine failure.

Engine Oil Maintenance Resources:
How to Check and Fill Motor Oil
What Happens if I Go Too Long Between Oil Changes?

The service vehicle light is a warning light that usually monitors several systems, and can also function as a backup warning light in the case that other warning lights have malfunctioned. If your service vehicle light is active, then it should be addressed as soon as possible. It can be a reminder of a routine service interval, or it could indicate a more serious issue with a variety of critical onboard systems. Refer to your vehicle's owner’s manual for specific causes of the service warning light.

Vehicle Service/Maintenance Resources:
How to Change Motor Oil
Routine Maintenance Checklist

The tire pressure monitoring system (TPMS) warning light activates when one or more tires are at pressure levels that exceed a specific threshold above or below the vehicle manufacturer's specification for safe driving. In some cases, a failing TPMS sensor can cause inaccurate readings or trigger the light to alert you that the system requires service. It's important that you check your tire pressure as soon as possible, and correct the tire pressure to reach the recommended level. The appropriate tire pressure for your vehicle can be found in your vehicle's owner's manual, or on a sticker along your vehicle's door jamb.

Note: It is not recommended that you use the pressure recommendation listed on the tire’s sidewall, as that is typically the maximum PSI rating for the tire and inflating to this level may damage the tire or affect driveability and handling.

Tire Pressure Resources:
How to Check Tire Pressure
How to Check Tire Tread and When to Replace Tires
What to Do When Your TPMS Light is On

When your vehicle displays a brake system warning light, it can mean the emergency or parking brake is engaged, your brake fluid levels are dangerously low, or there's a failure or loss of pressure in one or more areas of the braking system. If releasing your parking brake doesn’t turn this light off, it's recommended that you not drive the vehicle until you check the brake fluid level and condition, inspect the system for leaks, and repair any issues to ensure your vehicle can stop safely.

Brake System Resources:
Symptoms of Brake Component Failure
How to Bleed Brakes
Why Are My Brakes Grinding?

The anti-lock braking system (ABS) warning light indicates that your vehicle's ABS system is malfunctioning and may require service. In most cases, the ABS control module will store a diagnostic trouble code (DTC) that provides details of what triggered the warning. Any professional service center or repair shop should be able to scan the stored codes in the ABS module to determine what may be causing the warning light or any other ABS issues.

If your vehicle has a dedicated brake fluid level warning light, then you may see this light active if you experience low brake fluid levels. Similar to a brake system warning light, it's important to inspect your brake system for any brake fluid leaks and top off the brake fluid levels, but before continuing to drive your vehicle you will need to perform a thorough diagnosis so you can be sure you are able to brake safely. The brake system is sealed, so no fluid loss should occur without a leak or other damage to one or more hydraulic components.

Brake Fluid Resources:
How to Check and Fill Brake Fluid

The brake pad warning light indicates your brake pads are too thin and have worn down to the brake pad sensors. When this contact triggers the warning light, it's time to service your brakes and replace your brake pads.

Brake Pad Resources:
How to Change Brake Pads and Rotors
When to Change Your Brake Pads
What Brake Pads are Best for My Vehicle?

The gas cap warning light is designed to alert you to a loose or missing gas cap, which helps prevent evaporative emissions system leaks or fuel contamination. The best-case scenario when this light comes on is that your gas cap is not sealed completely and a quick re-tightening will turn off the warning light. If your check fuel cap light does not turn off, then it may indicate a leak from the gas cap, the fuel system, or a malfunctioning warning light, and you should have your vehicle inspected for any potential issues.

This type of warning light is related to the anti-theft system, and can mean there is an issue with this system recognizing the proper transponder-equipped key. This may prevent your vehicle from starting, or it may cause the vehicle to start and quickly die due to unrecognized electronic security protocols.

The lamp out indicator alerts you to a bulb or lighting system failure. In most cases this light will come on if there is a malfunctioning headlight or tail light, either from a burnt-out bulb or lamp or from an electrical system or connection failure near the bulb. If the bulb has simply burned out, any non-working bulb should be replaced to ensure proper visibility while driving. In other cases, more severe damage – including wiring harness or connector damage, blown fuses, or non-working relays – could also lead to a lamp out indicator that cannot be remedied by simply replacing the bulb.

Lighting Replacement Resources:
How to Fix Hyper-Flashing LED Turn Signals
How to Replace Headlights
How to Replace Headlight Assemblies

The traction control, or stability control, warning light can activate any time the traction control system is engaged. Usually, this only occurs on wet or slippery roads when your vehicle’s traction control system detects a loss of traction. If the traction control light is on or flashing for an extended period during normal driving conditions, then it may indicate an issue with your traction control system, wheel speed sensors, or other related components.

The airbag warning light is designed to alert you to an issue with one or more of your airbags, and may be an indicator that some part of this system requires service. This will not keep your vehicle from being driven, but could lead to injury if your airbags do not deploy in the event of an accident, or if they deploy prematurely. If your airbag light is on and stays on while driving, it is recommended that you address this as soon as possible to ensure your continued safety.

When the washer fluid icon appears, it's a reminder to refill your windshield washer fluid reservoir as soon as possible. If you've filled your washer fluid recently, or if it seems to be full but the light hasn’t turned off, then you may have a leak in your washer fluid system or a malfunctioning sensor.

Washer Fluid Resources:
Windshield Washer Fluid Types

This warning light indicates that there is an issue with the start/stop systems or other associated electronics. It's best to identify the specific cause immediately. If you think this may be related to your vehicle’s starter, our parts professionals can test your starter for free on or off the vehicle.

The diesel particulate filter (DPF) warning light means your diesel vehicle's emissions airflow is being restricted due to soot buildup or a clogged filter. If soot levels are not reduced, there is a risk of the vehicle engaging limp mode. This may require the DPF to be cleaned or replaced depending on the severity of the clog.

The diesel exhaust fluid (DEF) warning light indicates your DEF tank level is low and should be refilled as soon as possible. It can also mean the DEF is contaminated, which is usually the result of adding diesel fuel to the DEF tank. The icon is typically amber or red, and if the warning is ignored, then speed will be throttled until the DEF tank is filled or the issue is resolved.

This light is also specific to diesel vehicles and indicates that there is too much water in the fuel. The water separator (a type of filter that removes water from the fuel) likely needs to be drained, or the sensor or filter may be malfunctioning.