1. Check Engine light
Perhaps the most notorious dashboard indicator, this yellow light appears as an outline of an engine, the words "Check Engine," or a combination. It's usually triggered by a fault in the emissions system, which includes a broad number of issues from bad spark plugs and faulty catalytic converters all the way to a gas cap not being screwed on correctly.
Because the Check Engine light is vague, it can be tempting to ignore it. But even if the light isn't accompanied by an obvious problem, the underlying issue may lead to premature engine wear, worse gas mileage, increased emissions, or all 3. As with any yellow dashboard light, take your car to a mechanic at the first opportunity.
STEADY: Most issues will prompt a steady Check Engine light, which indicates an issue that needs to be checked out soon but not immediately.
FLASHING: This indicates a more severe issue, such as a cylinder misfire. Don't drive the car any further than necessary to get to a trusted repair facility.