xkcd #3096: Check Engine

Title text:

They say it's probably safe to keep orbiting for a while, but if it stays on or starts flashing we might have to call someone.

Transcript:

[A pattern in the form of a "check engine" light (as displayed on a car's instrument panel) is shown on the surface of the Sun, in the bottom right quarter. The pattern has a pictogram of a motor on the top and the text "Check Engine" below it, both in orange inside a black square, matching the orange color of the Sun.]

[Caption below the panel:]
This new sunspot cluster has raised concern among astronomers

Source: https://xkcd.com/3096/

explainxkcd for #3096