Your Audi A4’s check engine light isn’t just an annoying glow—it’s a message from your car’s brain. From loose gas caps to misfires and sensor failures, knowing the cause early can save you money and ...

Q: A few weeks ago my 2001 Saturn’s “check engine” light came on. A friend told me to tighten the gas cap and it would make the light turn off. I did. About two weeks later, the light went out. Was it ...

When your vehicle's check engine light (CEL) comes on, it's often a sign that something needs attention. But with over 20,000 parts working together in your car — many important for normal operation — ...

The check engine light has always been a bit of a gamble. Sometimes it’s a loose gas cap. Other times, it’s a four-figure ...

In a recent column, you talked about how a vehicle’s emissions system monitors itself for leaks. And that if a gas cap is loose and lets vapors escape, that will turn on the check engine light. Well, ...