35 common symptoms: warning lights, noises, smells, smoke, puddles and how the car drives or brakes. For each one, the most common causes, how urgent it is and what to do. It does not replace a mechanic: it helps you decide if you can keep driving and what to tell them.
On the dashboard, green or blue means a feature is on, yellow or orange is a warning and red is serious. Each automaker uses its own symbols: your owner’s manual explains them.
35 symptoms
Most common causes
What to do: Pull over and turn the engine off: driving without oil pressure can ruin the engine fast. When it cools, check the dipstick. If you add oil and the light comes back on, have it towed.
Source: AAA: dashboard lights
Most common causes
What to do: Turn on your hazards, pull over and turn the engine off. Get everyone out and away from traffic and call for a tow. Adding coolant yourself and driving on is dangerous: hot coolant can burn you.
Car overheating: pull over, then whatSource: AAA: overheating, AAA: dashboard lights
Most common causes
What to do: It points to the charging system, not only the battery. Turn off the radio, AC and chargers and drive straight to a shop: once the battery runs down, the car can stall.
Most common causes
What to do: First make sure the parking brake is fully released. If the light stays on, do not drive the car until the brakes are checked.
Brake repair cost: pads, rotors, calipers and fluidSource: AAA: dashboard lights
Most common causes
What to do: If you just filled up, tighten the gas cap and drive a few days to see if it goes off. If not, have the code read at a shop. It needs attention, but not a roadside stop.
Check engine light flashing: can I keep driving?Source: AAA: common car problems, AAA: dashboard lights
Most common causes
What to do: A flashing light is more serious than a steady one. Avoid driving further: pull over, turn the engine off and get a tow or a mobile mechanic.
Check engine light flashing: can I keep driving?Source: AAA: common car problems
Most common causes
What to do: Check all four tires with a gauge as soon as you can and fill them to the pressure on the sticker inside the driver’s door. If the light flashes for about a minute at start-up and then stays on, the sensor system itself has a fault.
Source: NHTSA: tires, NHTSA: FMVSS 138, AAA: common car problems
Most common causes
What to do: A short squeak when the brakes are wet is normal; a sharp squeal every time is not. Get a brake inspection as soon as possible, before it turns into grinding.
Brake repair cost: pads, rotors, calipers and fluidSource: AAA: smells and noises, AAA: common car problems
Most common causes
What to do: The car stops worse and the rotors get damaged with every stop. Have it checked as soon as possible and drive only short, slow trips until then. If the pedal goes soft, stop driving.
Brakes grinding: what it means and how far you can driveBrake repair cost: pads, rotors, calipers and fluid
Most common causes
What to do: Have a technician find where it comes from. Tell them if it happens on bumps, turns or both.
Source: AAA: smells and noises
Most common causes
What to do: Check the power steering fluid first (look for a red or pink leak). If the belt snaps you lose power steering, so do not wait long.
Source: AAA: smells and noises
Most common causes
What to do: Fill up with the octane in your owner’s manual. If the noise stays, have the ignition checked. A deep, rhythmic knock that gets louder is different: it can mean low oil or worn engine parts, so get it checked soon.
Most common causes
What to do: A jump start tells you a lot: if it starts and keeps running, test the battery; if it dies again, check the alternator. A mobile mechanic can test both where the car is.
Source: AAA: common car problems
Most common causes
What to do: That is a slipping transmission. Get it diagnosed soon: low fluid can overheat it and turn a small repair into a rebuild.
Source: AAA: common car problems
Most common causes
What to do: Watch the temperature gauge and go to a shop right away: a coolant leak leads to overheating.
Car overheating: pull over, then whatSource: AAA: smells and noises, AAA: common car problems
Most common causes
What to do: Have it fixed before your state emissions inspection, and sooner if the check engine light is on.
Source: AAA: smells and noises
Most common causes
What to do: Have a professional inspect it before you drive much more. If you see smoke from the dash or hood, pull over and turn the engine off.
Source: AAA: smells and noises
Most common causes
What to do: Overheated brakes stop worse and can fail. Pull over somewhere safe and let them cool. If it smells like this after normal driving (not a long downhill), a caliper may be stuck: have the car checked before you drive it more. On long downhills, use a lower gear.
Brake repair cost: pads, rotors, calipers and fluidSource: AAA: common car problems
Most common causes
What to do: Book a visit so a shop can find where the water comes in.
Source: AAA: smells and noises
Most common causes
What to do: A fuel leak is a fire risk. Do not start the car, keep sparks and cigarettes away and call for a tow or a mobile mechanic. A faint smell right after filling up that goes away is normal.
Most common causes
What to do: Pull over, turn the engine off and step away from the car. Do not open the hood or the radiator cap while it is hot. Call for a tow.
Car overheating: pull over, then whatSource: AAA: common car problems, AAA: overheating
Most common causes
What to do: Check the oil level often until it is fixed: running low on oil damages the engine.
Most common causes
What to do: Watch the temperature gauge and have it checked soon. A thin white vapor on a cold morning that goes away in a few minutes is just condensation.
Most common causes
What to do: It wastes gas and can fail an emissions test. Have the engine checked soon.
Most common causes
What to do: Check the dipstick and keep the oil topped up until it is fixed. Ignoring an oil leak can damage the engine.
Source: AAA: common car problems
Most common causes
What to do: Watch the temperature gauge and have it fixed soon. Coolant is toxic and its sweet taste attracts pets and kids: clean it up.
Car overheating: pull over, then whatSource: AAA: common car problems
Most common causes
What to do: Low transmission fluid causes slipping, overheating and transmission failure. Get it checked soon.
Source: AAA: common car problems
Most common causes
What to do: A brake fluid leak affects how the car stops. Do not drive it: get a tow or a mobile mechanic.
Brake repair cost: pads, rotors, calipers and fluidSource: AAA: common car problems
Most common causes
What to do: Steering gets hard and the pump can get damaged. Have it fixed soon.
Source: AAA: common car problems
Most common causes
What to do: Nothing to fix if it is plain water with no smell or color.
Most common causes
What to do: The pedal goes farther before the car stops. Do not drive it: get a tow or a mobile mechanic.
Brake repair cost: pads, rotors, calipers and fluidSource: AAA: common car problems
Most common causes
What to do: The rotors need resurfacing or replacing. Get a brake inspection soon.
Brake repair cost: pads, rotors, calipers and fluidSource: AAA: common car problems
Most common causes
What to do: Have the brakes checked soon. If it pulls hard, stop driving.
Brake repair cost: pads, rotors, calipers and fluidSource: AAA: common car problems
Most common causes
What to do: Check pressure monthly and before long trips, and rotate tires every 5,000 to 7,000 miles. Quarter test: if you see all of Washington’s head, the tread is under 4/32 inch.
Source: AAA: common car problems, NHTSA: tires
Most common causes
What to do: Not a safety problem for the car, but in summer heat it can be for kids, older people and pets. Ask the shop to find the leak before recharging.
Green or blue means a feature is on. Yellow or orange is a warning: get it checked soon, and you can usually still drive a few miles. Red is serious: stop as soon as it is safe.
If it is steady, usually yes for a short time, but have the code read soon (a loose gas cap is a common cause). If it is flashing, avoid driving: it signals a more serious problem.
Black or dark brown and greasy is engine oil. Green, orange, pink or blue and sweet is coolant. Red or reddish-brown is usually transmission fluid. Clear to light yellow with a fishy smell is brake fluid. Clear water under the front with the AC on is normal condensation.
Turn on your hazards, pull over and turn off the engine, get everyone away from traffic and call for a tow. Do not open the radiator cap while it is hot and do not keep driving after adding coolant.
Air pressure drops when it gets cold. If a tire is only slightly low, it can fall under the warning limit overnight and rise again as the tires warm up. Check and fill all four tires to the pressure on the driver’s door sticker.
Checked October 22, 2026. A few tips (gasoline smell, smoke color, car AC) are general safety and repair practice.