Truck & Car Guides / Car guides
Car maintenance and warning lights
The basic maintenance every car needs, how to check tires, oil and fluids yourself, and what the most common dashboard warning lights mean and how urgent they are.
Follow your owner's manual first
Every car has a maintenance schedule in its owner's manual, set by the manufacturer for that engine and model. It is more reliable than generic advice or a shop's sticker. Many modern cars also have a maintenance minder that calculates when service is due based on how you drive. This guide covers the general basics.
General education only. If you are unsure about a warning light or a repair, consult your manual or a qualified mechanic. Never work under a car supported only by a jack.
The core maintenance items
| Item | What it does | Typical guidance |
|---|---|---|
| Engine oil and filter | Lubricates and cools the engine | Follow the manual; many modern cars with synthetic oil go 5,000 to 10,000 miles or more |
| Tire pressure | Safety, handling, fuel economy, tire life | Check monthly when tires are cold |
| Tire rotation | Evens out wear | Often every 5,000 to 7,500 miles |
| Brake pads and fluid | Stopping power | Inspect regularly; brake fluid is changed every few years on many cars |
| Coolant | Prevents overheating and freezing | Check level; replace per manual |
| Air filters | Clean air for engine and cabin | Inspect yearly or per manual |
| Wiper blades | Visibility | Replace when streaking, often about once a year |
| Battery | Starting power | Many last around three to five years; extreme heat and cold shorten life |
Checks you can do yourself
Tire pressure. Use the pressure on the sticker inside the driver's door jamb, not the maximum printed on the tire sidewall. Check when the tires are cold. US cars from the 2008 model year onward have a tire pressure monitoring system (TPMS) that warns when pressure is significantly low, but it is not a substitute for a gauge.
Tread depth. Many US states set a legal minimum of 2/32 inch. A quick test is to place a penny head-first in the tread: if you can see the top of Lincoln's head, the tread is very worn. Traction in rain and snow drops well before the legal limit, so many experts suggest replacing tires sooner.
Oil level. On cars with a dipstick, check with the engine off and on level ground. The level should be between the two marks.
Fluids and lights. Glance at coolant and washer fluid levels, and walk around the car to check that all lights work.
Warning light colors
Dashboard lights follow a rough color code:
- Red: serious problem or safety issue. Stop safely as soon as possible and investigate.
- Yellow or amber: something needs attention soon.
- Green or blue: a system is on, such as headlights or cruise control.
Common warning lights
| Light | Meaning | What to do |
|---|---|---|
| Check engine (steady) | The engine computer detected a fault | Get it diagnosed soon; check the gas cap is tight |
| Check engine (flashing) | Often a severe misfire that can damage the catalytic converter | Reduce speed and get it checked right away |
| Oil pressure (red oil can) | Low oil pressure | Stop safely and turn off the engine; check oil level |
| Temperature | Engine overheating | Pull over, turn off the engine, let it cool; never open a hot radiator cap |
| Battery or charging | Charging system problem | Head to a shop; the car may stop when the battery drains |
| Brake system | Parking brake on, low brake fluid or brake fault | Check parking brake; if it stays on, get brakes checked before driving far |
| ABS | Anti-lock braking fault | Normal brakes usually still work; get it checked |
| TPMS | Low tire pressure | Check and inflate tires |
An inexpensive OBD-II code reader plugs into the port under the dashboard of US cars from 1996 onward and shows the code behind a check engine light. It helps you have a better conversation with your mechanic.