Check engine light (engine malfunction)

The engine's on-board diagnostics have detected a malfunction in the engine or its emission controls. UN R121 lists it as “Engine on-board diagnostics or engine malfunction” and makes it yellow. FMVSS 101 does not list this lamp.

Yellow / amber

What to do

Have the stored fault code read soon — any garage can, and the code narrows the problem down. If the lamp flashes, or the engine runs roughly, shakes or loses power, reduce speed and load and have it checked promptly; what a flashing lamp means is set by the maker, so check the manual.

Makes differ: what this light means on your car, the other colours it may use for the symbol and what the car wants you to do are set by the manufacturer, so your car's owner's manual is the authority.

Symbol: Outline of an engine
Colour: Yellow / amber

What the colour means

Yellow / amber — “caution”

The same colour code (Directive 2009/80/EC, Annex I, 2.1.4) gives “amber: caution”. FMVSS 101 and UN R121 write the colour as “yellow”; it is the colour both tables give to malfunction telltales such as ABS, stability control and low tyre pressure.

Where the regulations list it

Rule	Row	Colour it sets
UN R121	Table, item 30 “Engine on-board diagnostics or engine malfunction” — tell-tale	yellow

UN R121: Cars (category M) and light goods vehicles (N1) type-approved under the UN 1958 Agreement, which includes the EU, UK and Japan (para 1). Its table gives the symbol and colour of each tell-tale; note 2 says the symbols are substantially identical to those of ISO 2575:2004.

Other yellow / amber lights

ABS warning light (anti-lock brakes)ABS in a circle between two arcs Brake pad wear warning lightCircle between two dashed arcs · also red Airbag warning lightSeated person facing a round airbag · also red Side airbag warning lightSeated person with an airbag beside them · also red Passenger airbag off lightCrossed-out airbag beside a seated person Low tyre pressure light (TPMS)Tyre cross-section with an !Low tyre pressure light showing which tyreCar seen from above, four wheels TPMS light (tyre pressure monitor fault)The letters TPMS Stability control light (ESC)Car with two wavy skid marks Stability control off light (ESC OFF)Skidding car with OFF underneath Low fuel lightFuel pump with a hose Rear fog light indicatorLamp facing right, straight beams, wavy line Glow plug light (diesel pre-heat)A coil of wire Choke light (cold-start device)Tilted valve between two bars Windscreen defrost lightCurved windscreen with three wavy arrows Rear window defrost lightRectangle with three wavy arrows

Sources

Meanings are written in our own words from these public texts, not quoted from ISO 2575, and were checked on the date shown.