Which color indicates that a spark plug has been checked and is okay?

The color that indicates a spark plug has been checked and is okay is green. In automotive maintenance, colors are often used as a visual shorthand to convey the status of various components. Green typically signifies that a part has passed inspection and is in good working condition. This standardized color-coding helps technicians quickly assess the health of components during routine checks, ensuring efficient service and maintenance.

In this context, while other colors like purple, yellow, or red may have specific meanings in different contexts or organizations, green is universally understood within the realm of automotive inspection to denote that the spark plug is functioning properly and does not require further action at this time. This allows for streamlined communication and operational efficiency in a busy service environment like Jiffy Lube.