Check engine light
The warning light a vehicle's on-board diagnostics (OBD) system turns on when it detects a problem or malfunction.
Dashboard symbols vary by manufacturer. The vehicle's owner's manual or a qualified mechanic can say what a light means for a particular vehicle.
How to read it
The symbol is an engine drawn in outline. According to the California Air Resources Board, the light will typically display the words "Check Engine" or "Service Engine Soon" and often includes an engine symbol. Ford's F-150 manual calls it Service Engine Soon: lit with the engine running, it means the on-board diagnostics system has detected a malfunction of the vehicle emission control system, and flashing, that an engine misfire may be occurring.
Also searched as: engine light, malfunction indicator lamp, MIL.
Differences by country or standard
The U.S. Environmental Protection Agency requires all 1996 and newer passenger cars and trucks sold in any state to meet its OBD requirements, which differ slightly from California's, according to the California Air Resources Board.
More dashboard warning lights
Sources
- 2020 F-150 Owner's Manual, Ford Motor Company, Instrument Cluster: Warning Lamps and Indicators
- On-Board Diagnostic II (OBD II) Systems Fact Sheet, California Air Resources Board
Last reviewed September 25, 2026 by Rory Hansen. How we research