Oil pressure warning light (oil can)
The engine oil pressure warning. UN R121 makes this tell-tale red; FMVSS 101 requires the oil-can symbol and the word “Oil” but sets no colour. A red oil can reports a problem with the pressure of the oil that lubricates the engine.
Red
What to do
Stop as soon as you can do so safely and switch the engine off — an engine running without enough oil pressure can be damaged within minutes. Check the oil level with the dipstick once the car has stood for a few minutes, and read the manual before restarting.
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
- Oil can with a drip
- Colour
- Red
What the colour means
Red — “danger”
The colour code that UN R121 points to (ISO 2575, paragraph 5) is sold, not published. The EU wrote it into law for two- and three-wheel vehicles in Directive 2009/80/EC, Annex I, 2.1.4: “red: danger”. FMVSS 101 does not define colour meanings, but S5.5.6(b) says a telltale for which red is required must not be cancelable while its underlying condition exists, and note 4 to Table 1 allows red to be red-orange.
Where the regulations list it
| Rule | Row | Colour it sets |
|---|---|---|
| FMVSS 101 | Table 1, “Engine oil pressure” — telltale and indicator, word “Oil” | no colour required |
| UN R121 | Table, item 10 “Engine oil pressure” — tell-tale | red |
FMVSS 101: Passenger cars, multipurpose passenger vehicles, trucks and buses sold in the US (S3). Table 1 gives the symbol or words and, where one is required, the colour of each telltale; Table 2 lists identifiers with no colour requirement. 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.
Good to know
- UN R121 note 18 allows this symbol in other colours to convey other meanings, so a yellow oil can on some cars reports a different, manufacturer-defined condition.
- Both rules allow the oil and coolant symbols to be combined in one telltale (FMVSS 101 note 13, UN R121 note 5).
Other red lights
Sources
- eCFR — 49 CFR 571.101, Standard No. 101; Controls and displays (current text) — checked 2026-09-23
- govinfo — 49 CFR 571.101 in the Code of Federal Regulations, 1 October 2025 edition (Tables 1 and 2 as printed) — checked 2026-09-23
- EUR-Lex — UN Regulation No. 121 (01 series), Official Journal of the EU L 5, 8 January 2016: table 'Symbols, their illumination and colours' — checked 2026-09-23
- Directive 2009/80/EC, Annex I, point 2.1.4 — the tell-tale colour meanings as written into EU law (for two- and three-wheel vehicles) — checked 2026-09-23
Meanings are written in our own words from these public texts, not quoted from ISO 2575, and were checked on the date shown.