# Car symptom checker: what’s wrong with my car?

Warning lights, noises, smells, smoke and puddles: what each likely means, how urgent it is and what to do before calling a mechanic. Sources: AAA, NHTSA.

- **Stop driving**: Pull over when it is safe and turn the engine off. Get a tow or a mobile mechanic.
- **Get it checked soon**: You can usually drive a few miles, for example to a shop, but get it checked in the next few days.
- **Can wait for a regular visit**: Not a safety problem by itself. Mention it at your next service.

## Warning lights

### Red oil can light (oil pressure)

Urgency: Stop driving

- Low engine oil
- Oil pump problem

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 Oregon/Idaho: What’s your car trying to tell you with that dashboard light?](https://info.oregon.aaa.com/whats-your-car-trying-to-tell-you-with-that-dashboard-light/)

### Temperature light or gauge in the red

Urgency: Stop driving

- Low coolant from a leak (hose, radiator, water pump)
- Thermostat stuck closed
- Broken radiator fan or loose belt
- Blown head gasket

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.
- Guide: [Car overheating: pull over, then what](https://pros411.com/en/guides/mechanics/car-overheating)
- Source: [AAA: Car Overheating, 8 Causes and Solutions](https://www.aaa.com/autorepair/articles/car-overheating-8-causes-and-solutions)
- Source: [AAA Oregon/Idaho: What’s your car trying to tell you with that dashboard light?](https://info.oregon.aaa.com/whats-your-car-trying-to-tell-you-with-that-dashboard-light/)

### Battery light while driving

Urgency: Get it checked soon

- Failing alternator
- Worn battery
- Loose or corroded wire

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.
- Source: [AAA Oregon/Idaho: What’s your car trying to tell you with that dashboard light?](https://info.oregon.aaa.com/whats-your-car-trying-to-tell-you-with-that-dashboard-light/)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Red BRAKE light stays on

Urgency: Stop driving

- Parking brake still on
- Low brake fluid
- Problem in the brake system

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.
- Guide: [Brake repair cost: pads, rotors, calipers and fluid](https://pros411.com/en/guides/mechanics/brake-repair-cost)
- Source: [AAA Oregon/Idaho: What’s your car trying to tell you with that dashboard light?](https://info.oregon.aaa.com/whats-your-car-trying-to-tell-you-with-that-dashboard-light/)

### Check engine light, steady

Urgency: Get it checked soon

- Loose gas cap (very common)
- Bad oxygen sensor
- Other engine or emissions fault

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.
- Guide: [Check engine light flashing: can I keep driving?](https://pros411.com/en/guides/mechanics/check-engine-light-flashing)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)
- Source: [AAA Oregon/Idaho: What’s your car trying to tell you with that dashboard light?](https://info.oregon.aaa.com/whats-your-car-trying-to-tell-you-with-that-dashboard-light/)

### Check engine light flashing

Urgency: Stop driving

- Serious engine misfire
- Problem that can overheat and damage the catalytic converter

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.
- Guide: [Check engine light flashing: can I keep driving?](https://pros411.com/en/guides/mechanics/check-engine-light-flashing)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Tire pressure light (TPMS)

Urgency: Get it checked soon

- One or more tires 25% or more below the recommended pressure
- Nail or puncture, or a damaged valve stem
- Cold morning: pressure that is barely low drops under the limit overnight

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: Tire Safety](https://www.nhtsa.gov/vehicle-safety/tires)
- Source: [NHTSA: FMVSS No. 138, Tire Pressure Monitoring Systems](https://www.nhtsa.gov/sites/nhtsa.gov/files/fmvss/TPMS-2005-FMVSS-No138.pdf)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

## Noises

### High-pitched squeal when braking

Urgency: Get it checked soon

- Brake pads worn down to the wear indicator

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.
- Guide: [Brake repair cost: pads, rotors, calipers and fluid](https://pros411.com/en/guides/mechanics/brake-repair-cost)
- Source: [AAA Club Alliance: What does that strange car smell or weird noise mean? (Feb 20, 2020)](https://cluballiance.aaa.com/en/the-extra-mile/articles/prepare/car/what-does-that-strange-car-smell-or-weird-noise-mean)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Grinding when braking

Urgency: Get it checked soon

- Pads worn through: metal on the rotor

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.
- Guide: [Brakes grinding: what it means and how far you can drive](https://pros411.com/en/guides/mechanics/brakes-grinding)
- Guide: [Brake repair cost: pads, rotors, calipers and fluid](https://pros411.com/en/guides/mechanics/brake-repair-cost)

### Clunk over bumps

Urgency: Get it checked soon

- Loose or worn shock absorber
- Loose exhaust pipe

What to do: Have a technician find where it comes from. Tell them if it happens on bumps, turns or both.
- Source: [AAA Club Alliance: What does that strange car smell or weird noise mean? (Feb 20, 2020)](https://cluballiance.aaa.com/en/the-extra-mile/articles/prepare/car/what-does-that-strange-car-smell-or-weird-noise-mean)

### Squeal when turning the steering wheel

Urgency: Get it checked soon

- Low power steering fluid
- Worn belt that is slipping

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 Club Alliance: What does that strange car smell or weird noise mean? (Feb 20, 2020)](https://cluballiance.aaa.com/en/the-extra-mile/articles/prepare/car/what-does-that-strange-car-smell-or-weird-noise-mean)

### Pinging or light tapping when you accelerate

Urgency: Can wait for a regular visit

- Gas with lower octane than your car needs
- Ignition timing

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.
- Source: [AAA Club Alliance: What does that strange car smell or weird noise mean? (Feb 20, 2020)](https://cluballiance.aaa.com/en/the-extra-mile/articles/prepare/car/what-does-that-strange-car-smell-or-weird-noise-mean)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Clicking and the car won’t start

Urgency: Get it checked soon

- Fast clicking: weak or dead battery
- One click or nothing with a good battery: starter
- Cranks slowly or dies after a jump: alternator

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: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Whining and the engine revs but the car barely speeds up

Urgency: Get it checked soon

- Low or burnt transmission fluid
- Worn clutches or bands inside the transmission
- Torque converter problem

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: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

## Smells

### Sweet, syrupy smell

Urgency: Get it checked soon

- Coolant (antifreeze) leak

What to do: Watch the temperature gauge and go to a shop right away: a coolant leak leads to overheating.
- Guide: [Car overheating: pull over, then what](https://pros411.com/en/guides/mechanics/car-overheating)
- Source: [AAA Club Alliance: What does that strange car smell or weird noise mean? (Feb 20, 2020)](https://cluballiance.aaa.com/en/the-extra-mile/articles/prepare/car/what-does-that-strange-car-smell-or-weird-noise-mean)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Rotten egg smell

Urgency: Get it checked soon

- Catalytic converter or emissions system problem

What to do: Have it fixed before your state emissions inspection, and sooner if the check engine light is on.
- Source: [AAA Club Alliance: What does that strange car smell or weird noise mean? (Feb 20, 2020)](https://cluballiance.aaa.com/en/the-extra-mile/articles/prepare/car/what-does-that-strange-car-smell-or-weird-noise-mean)

### Burnt toast or burning plastic

Urgency: Get it checked soon

- Electrical short burning wire insulation

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 Club Alliance: What does that strange car smell or weird noise mean? (Feb 20, 2020)](https://cluballiance.aaa.com/en/the-extra-mile/articles/prepare/car/what-does-that-strange-car-smell-or-weird-noise-mean)

### Hot, burning smell near a wheel after braking

Urgency: Stop driving

- Overheated brakes
- Brake caliper sticking

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.
- Guide: [Brake repair cost: pads, rotors, calipers and fluid](https://pros411.com/en/guides/mechanics/brake-repair-cost)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Musty or moldy smell inside

Urgency: Can wait for a regular visit

- Water leaking in: check under the floor mats for damp spots

What to do: Book a visit so a shop can find where the water comes in.
- Source: [AAA Club Alliance: What does that strange car smell or weird noise mean? (Feb 20, 2020)](https://cluballiance.aaa.com/en/the-extra-mile/articles/prepare/car/what-does-that-strange-car-smell-or-weird-noise-mean)

### Strong smell of raw gasoline

Urgency: Stop driving

- Fuel leak from a line, the tank or the injectors

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.

## Smoke and steam

### Steam from under the hood

Urgency: Stop driving

- Engine overheating, usually from low coolant

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.
- Guide: [Car overheating: pull over, then what](https://pros411.com/en/guides/mechanics/car-overheating)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)
- Source: [AAA: Car Overheating, 8 Causes and Solutions](https://www.aaa.com/autorepair/articles/car-overheating-8-causes-and-solutions)

### Blue or gray smoke from the exhaust

Urgency: Get it checked soon

- The engine is burning oil (worn seals or rings, turbo seal)

What to do: Check the oil level often until it is fixed: running low on oil damages the engine.

### Thick white smoke that smells sweet

Urgency: Get it checked soon

- Coolant getting into the engine (head gasket)

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.
- Guide: [Car overheating: pull over, then what](https://pros411.com/en/guides/mechanics/car-overheating)

### Black smoke from the exhaust

Urgency: Get it checked soon

- The engine is getting too much fuel: clogged air filter, leaking injector or a bad sensor

What to do: It wastes gas and can fail an emissions test. Have the engine checked soon.

## Puddles and leaks

### Dark brown or black, greasy puddle

Urgency: Get it checked soon

- Engine oil: worn gasket or damaged oil line

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: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Green, orange, pink or blue puddle that smells sweet

Urgency: Get it checked soon

- Coolant: cracked hose, leaking radiator or bad water pump

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.
- Guide: [Car overheating: pull over, then what](https://pros411.com/en/guides/mechanics/car-overheating)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Red or reddish-brown, oily puddle

Urgency: Get it checked soon

- Transmission fluid
- Power steering fluid in some cars

What to do: Low transmission fluid causes slipping, overheating and transmission failure. Get it checked soon.
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Clear to light yellow, slippery, fishy smell

Urgency: Stop driving

- Brake fluid leak

What to do: A brake fluid leak affects how the car stops. Do not drive it: get a tow or a mobile mechanic.
- Guide: [Brake repair cost: pads, rotors, calipers and fluid](https://pros411.com/en/guides/mechanics/brake-repair-cost)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Clear to amber, slightly oily

Urgency: Get it checked soon

- Power steering fluid

What to do: Steering gets hard and the pump can get damaged. Have it fixed soon.
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Clear water dripping under the front, with the AC on

Urgency: Can wait for a regular visit

- Normal condensation from the air conditioning

What to do: Nothing to fix if it is plain water with no smell or color.

## How it drives and brakes

### Soft or spongy brake pedal

Urgency: Stop driving

- Air in the brake lines
- Brake fluid leak

What to do: The pedal goes farther before the car stops. Do not drive it: get a tow or a mobile mechanic.
- Guide: [Brake repair cost: pads, rotors, calipers and fluid](https://pros411.com/en/guides/mechanics/brake-repair-cost)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Brake pedal or steering wheel pulses when braking

Urgency: Get it checked soon

- Warped rotors

What to do: The rotors need resurfacing or replacing. Get a brake inspection soon.
- Guide: [Brake repair cost: pads, rotors, calipers and fluid](https://pros411.com/en/guides/mechanics/brake-repair-cost)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Car pulls to one side when braking

Urgency: Get it checked soon

- Sticking brake caliper
- Uneven brake wear

What to do: Have the brakes checked soon. If it pulls hard, stop driving.
- Guide: [Brake repair cost: pads, rotors, calipers and fluid](https://pros411.com/en/guides/mechanics/brake-repair-cost)
- Source: [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)

### Tires wearing unevenly or the car drifts to one side

Urgency: Can wait for a regular visit

- Edges worn: tires underinflated
- Center worn: tires overinflated
- One side worn: wheels out of alignment

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: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)
- Source: [NHTSA: Tire Safety](https://www.nhtsa.gov/vehicle-safety/tires)

### AC blows warm air

Urgency: Can wait for a regular visit

- Refrigerant leak (low charge)
- Compressor or compressor clutch
- Blend door or electrical fault

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.
- Guide: [Car AC repair cost: recharge, compressor, condenser](https://pros411.com/en/guides/mechanics/car-ac-repair-cost)

## Before you call a mechanic

- Write down when it happens: cold or warm engine, at what speed, when braking, turning or going over bumps.
- Take a photo of the warning light and note if it is steady or flashing.
- For a leak, slide a piece of white cardboard under the car overnight: the color and spot tell the mechanic a lot.
- Have the year, make, model and mileage ready. Your owner’s manual explains every light on your dashboard.
- If the car is not safe to drive, ask for a mobile mechanic or a tow instead of driving it to the shop.

## Frequently asked questions

### What do the colors of dashboard lights mean?

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.

### Can I drive with the check engine light on?

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.

### What color is the fluid leaking from my car?

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.

### What should I do if my car overheats?

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.

### Why is my tire pressure light on when it is cold?

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.

## Sources

- [AAA: 13 Common Car Problems Explained](https://www.aaa.com/autorepair/articles/13-common-car-problems-explained)
- [AAA: Car Overheating, 8 Causes and Solutions](https://www.aaa.com/autorepair/articles/car-overheating-8-causes-and-solutions)
- [AAA Club Alliance: What does that strange car smell or weird noise mean? (Feb 20, 2020)](https://cluballiance.aaa.com/en/the-extra-mile/articles/prepare/car/what-does-that-strange-car-smell-or-weird-noise-mean)
- [AAA Oregon/Idaho: What’s your car trying to tell you with that dashboard light?](https://info.oregon.aaa.com/whats-your-car-trying-to-tell-you-with-that-dashboard-light/)
- [NHTSA: Tire Safety](https://www.nhtsa.gov/vehicle-safety/tires)
- [NHTSA: FMVSS No. 138, Tire Pressure Monitoring Systems](https://www.nhtsa.gov/sites/nhtsa.gov/files/fmvss/TPMS-2005-FMVSS-No138.pdf)

Page with search: https://pros411.com/en/tools/car-symptom-checker