Dashboard warning lights follow a simple color code: red means stop or deal with it now, amber or yellow means get it checked soon, and green or blue just tells you a system is on. Knowing which group a light belongs to tells you most of what you need in the moment.
Symbols vary between makes and model years, so your owner's manual, which shows every light your car uses, is always the final word.
How warning light colors work
Most manufacturers use the same traffic-light logic:
- Red: a serious problem or safety risk. Stop as soon as it's safe, or don't drive on until you know what it means.
- Amber or yellow: a system needs attention or isn't working. Keep driving carefully and book a check soon.
- Green or blue: information only, such as headlights, high beams (blue), cruise control or an EV that's ready to drive.
A flashing light is usually more urgent than a steady one. Most lights glow briefly as a self-test when you switch on the ignition. Pay attention to any that stay on after the engine starts.
Common warning lights and what to do
Colors shown are typical and can differ by car.
Engine and powertrain
| Light | What it means | What to do |
|---|---|---|
| Check engine, steady (amber): an engine outline, sometimes with the words "check engine" | The engine computer has logged a fault, from a loose gas cap to a failing sensor. | Tighten the gas cap and get the code read within a few days. |
| Check engine, flashing (amber) | A severe misfire. Unburned fuel can overheat and destroy the catalytic converter. | Ease off, pull over when safe and arrange service. Avoid driving. |
| Oil pressure (red): an old-style oil can dripping from the spout | Oil pressure is too low to protect the engine. | Stop and switch off immediately. Check the oil level. Don't drive if the light stays on. |
| Coolant temperature (red): a thermometer standing in wavy lines of liquid | The engine is overheating. A blue version on some cars just means the engine is cold. | Pull over and switch off. Check coolant only once the engine has cooled. |
| Battery or charging (red): a rectangle with plus and minus terminals on top | The charging system has failed, so the car is running on battery power alone. | Turn off nonessential electrics and drive straight to a shop. |
| Transmission temperature (amber or red): a gear with a thermometer inside | Transmission fluid is overheating, often from towing, steep hills or hot, slow traffic. | Pull over and let it cool. Have the fluid checked if it recurs. |
| Low fuel (amber): a fuel pump | You're into the reserve. How far it lasts varies by car. | Refuel soon. Running dry can strand you and strain the fuel pump. |
Brakes, steering and safety systems
| Light | What it means | What to do |
|---|---|---|
| Brake system (red): an exclamation mark inside a circle between curved brackets, or the word "brake" | The parking brake is on, brake fluid is low or there's a hydraulic fault. | Release the parking brake. If the light stays on or the pedal feels soft, stop and have the car towed. |
| ABS (amber): the letters "ABS" inside a circle between brackets | Anti-lock braking is off. Normal brakes work, but wheels can lock in a hard stop. | Leave extra following distance and get it checked soon. |
| Tire pressure, TPMS (amber): a flat-bottomed horseshoe shape (a tire cross-section) with an exclamation mark inside | A tire is well below recommended pressure; US rules require a warning at 25% low. Flashing, then staying on, means a system fault. | Check all four tires cold against the door-jamb placard and inflate. Look for a puncture if one keeps losing air. |
| Airbag or SRS (usually red): a seated person in a seat belt with a large circle in front | A fault in the airbag or seat belt system. Airbags may not deploy in a crash. | Get it inspected promptly; check for recalls. |
| Traction or stability control (amber): a car with two wavy skid marks behind it | Flashing means it's working to stop a skid. Steady, or with "off", means it's switched off or faulty. | If flashing, ease off. If steady, check it isn't switched off, then get it checked. |
| Power steering (amber or red): a steering wheel with an exclamation mark | Steering assistance is reduced or gone, so steering gets much heavier. | Slow down, grip firmly and get it looked at before driving far. |
For more on tire pressure, see our tires 101 guide and NHTSA's tire safety pages.
Electric and diesel vehicles
| Light | What it means | What to do |
|---|---|---|
| Reduced power (amber): a turtle | Power is limited, usually because the battery is nearly empty, too hot or too cold, or has a fault. | Drive gently to a charger. If it appears with plenty of charge, book service. |
| High-voltage system fault (red or amber): varies by maker, often a car or battery outline with an exclamation mark, plus a text message | A problem in the high-voltage battery, motor or related electronics. | Follow the on-screen message. If you notice smoke or a burning smell, get everyone out and call emergency services. |
| Glow plug (amber): a coil of wire, like a spring on its side | The glow plugs are warming a cold diesel. Flashing while driving usually signals an engine fault. | Wait for it to go out before starting. If it flashes, get the code read. |
| Diesel particulate filter, DPF (amber): a rectangle filled with dots, often with a pipe at each end | The soot filter is clogging and needs to burn itself clean (regenerate). | A steady highway drive of roughly 15 to 20 minutes usually clears it; your manual gives the details. |
Using an OBD-II code reader
Cars sold in the US since the 1996 model year have a standard OBD-II port, and most other major markets adopted equivalents by the early 2000s. It's a 16-pin socket, usually under the dashboard near the steering column. Plug in a reader, turn the ignition on, and it shows the codes behind a check engine light.
Basic readers and Bluetooth adapters commonly cost $20 to $100, and many US auto parts stores read codes free. P0300, for example, means random cylinder misfires, and P0455 flags a large fuel vapor leak, often a loose gas cap. Keep three limits in mind:
- A code shows where a problem was detected, not always its cause.
- Clearing a code fixes nothing and resets emissions readiness checks, so you may fail an inspection until they complete.
- Basic readers usually can't read ABS, airbag or transmission codes.
In many places a lit check engine, airbag or ABS light can fail a safety or emissions test, so check your state, province or country rules before your test date.
When to stop driving immediately
Pull over as soon as it's safe and switch off the engine if you see:
- A flashing check engine light, especially with shaking or loss of power
- The red oil pressure or coolant temperature light, or steam from under the hood
- A red brake light with a soft or sinking pedal, or red brake and ABS lights together
- Any light combined with smoke, a burning smell, loud new noises or a sudden change in steering or braking
- An EV message telling you to stop safely
Turn on your hazard lights and call for roadside help rather than limping on. A tow costs far less than a new engine.
Watch out: Never open the radiator or coolant reservoir cap on a hot engine. The system is under pressure, and coolant can spray out hot enough to cause serious burns.
Warning lights, maintenance and your warranty
Many warning lights trace back to skipped maintenance. Our car maintenance schedule lists typical intervals, and the maintenance planner builds a reminder list for your car.
If your car is under warranty, report a light promptly so a covered repair stays covered. Some lights, airbag faults especially, are linked to safety recalls that are repaired free, so run your VIN through our recall check or NHTSA's recall lookup. Before you call a shop, note:
- The light's color and whether it was steady or flashing
- What you were doing: cold start, cruising, braking or towing
- Other symptoms, such as noises, smells, vibration or loss of power
- Any trouble code from a reader, plus the odometer reading
Key takeaway: Red means stop soon, amber means check soon, and green or blue is information. A flashing light outranks a steady one, and your owner's manual has the final say on any symbol.
The bottom line
You don't need to memorize every symbol. Learn the colors, treat any red or flashing light as a reason to stop, and get amber lights checked within days, not weeks. Whenever this guide and your owner's manual disagree, follow the manual.
Frequently asked questions
Can I keep driving with the check engine light on?
If it is steady and the car drives normally, you can usually drive gently for a short time, but tighten the gas cap and get the code read within a few days. If it is flashing, the engine is misfiring badly: slow down, pull over when it is safe and arrange service, because continued driving can ruin the catalytic converter.
What is the difference between a red and an amber warning light?
Red means a serious problem or safety risk, so stop as soon as it is safe or find out what it means before driving on. Amber or yellow means a system needs attention or is not working, so drive carefully and book a check soon. Green and blue lights are information only. Your owner's manual confirms the meaning for your car.
Why does my tire pressure light come on when it gets cold?
Air pressure drops by roughly 1 psi for every 10 degrees Fahrenheit fall in temperature, so a cold morning can push tires that were slightly low below the warning threshold. Check all four tires when cold against the placard in the driver's door jamb and inflate them. The light should go out after a short drive.
Will disconnecting the battery reset a warning light?
On some cars it clears stored codes and turns the check engine light off temporarily, but it does not fix anything and the light returns if the fault is still there. It can also erase emissions readiness data and electronic settings. Read the code first and fix the cause instead.