Warning lights
Dashboard warning lights: find a symbol and its meaning
Pick the symbol that looks like the one on your dashboard. Each card gives the light’s meaning under the federal rules, its color and what to do.
Which light is on?
or by its symbol
Check Engine / Service Engine Soon / engine symbol
Check engine light
Color: Amber (color not set by federal rule)
| On and steady | Moderate Keep driving gently and have the code read within days. |
| Flashing | Severe Stop as soon as it is safe: a misfire is damaging the catalytic converter. |
| Comes and goes | Moderate An intermittent fault: the code is stored even when the light is off. |
Worst case for this light: severe: stop when safe. Source: 40 CFR 86.1806-05(c): must show "Check Engine", "Service Engine Soon" or an engine symbol; must blink during catalyst-damaging misfire.
Most of the symbols on a US dashboard are not chosen freely by carmakers. Federal Motor Vehicle Safety Standard 101 (49 CFR 571.101) lists the telltales a vehicle may or must have, the symbol or words that identify each, and, for some, the color. The brake system warning must be red, the antilock, stability control and tire pressure warnings yellow, the high beam indicator blue or green. For others, such as oil pressure, coolant temperature and charging, the standard fixes the symbol but leaves the color to the maker, who usually uses red. The check engine light is defined separately in the emission rules (40 CFR 86.1806-05). As a rule of thumb, red means stop or act now, yellow or amber means a fault to have checked soon, and green or blue simply shows that something is on. Three warnings call for stopping the engine: oil pressure, overheating and the red brake light with a soft pedal.
Codes, rules and labor data checked by Radif Partners · Editorial policy · Method and sources
The common warning lights at a glance
| Light | Symbol or words | Color |
|---|---|---|
| Check engine light | Check Engine / Service Engine Soon / engine symbol | Amber (color not set by federal rule) |
| Tire pressure light | Horseshoe with an exclamation mark, or "Low Tire"; "TPMS" for a system fault | Yellow (required) |
| Traction control light | Car with two skid lines, or "ESC"; with "OFF" when switched off | Yellow (required) |
| ABS light | "ABS" or "Antilock" | Yellow (required) |
| Battery light | Battery symbol, or "Volts", "Charge", "Amp" | Not set by federal rule (usually red) |
| Oil pressure light | Oil can with a drop, or "Oil" | Not set by federal rule (usually red) |
| Airbag light | Seated person with a circle, or "Airbag" / "SRS" | Not set by federal rule (usually red) |
| Brake warning light | "Brake", "Park", "Brake Fluid" | Red (required) |
| Coolant temperature light | Thermometer in waves, or "Temp" | Not set by federal rule (red when hot) |
| Low fuel light | Fuel pump symbol, or "Fuel" | Not set by federal rule |
Red brake light
The red "BRAKE" telltale, required to be red by FMVSS 135, comes on when the parking brake is applied, when the brake fluid level is low, and on many cars when the brake system has a hydraulic or electronic fault. Release the parking brake first. If the light stays on, check the fluid level in the reservoir: low fluid usually means worn pads or a leak. If the pedal feels soft, goes lower than usual or the car pulls, stop driving and have it towed.
Coolant temperature light
A thermometer in waves, or the word "Temp", is the coolant temperature telltale. Red usually means the engine is overheating: switch off the air conditioning, turn the heater to full hot to shed heat, and stop as soon as it is safe. Do not open the radiator or reservoir cap while hot. A blue version on some cars only means the engine is still cold. A thermostat that keeps the engine too cold sets P0128 instead.
Low fuel light
The fuel pump symbol, or the word "Fuel", tells you the tank is low. How far you can go varies by car; the manual sometimes says. Running a tank dry can damage the fuel pump, which is cooled by fuel, and some cars then set fuel system codes. An arrow next to the symbol shows which side the filler is on.
Lights that are not warnings
Green and blue telltales show that a system is on: headlights, high beams (blue or green under the federal table), turn signals (green), cruise control. A wrench or "Service" message is a maintenance reminder by mileage. A "passenger airbag off" light shows the occupant sensor at work. None of these is a fault.
Lights from other modules
The check engine light is the only one whose codes every OBD-II reader can read. Codes behind the ABS, stability control and airbag lights live in their own modules and need a scanner that reads them. The code lookup explains how those C, B and U codes are built.