Ignition coil function is critical to your engine running properly, and a faulty ignition coil might cause a check engine light. Join Tim from AutoZone in this instructional video where he explains the signs and symptoms of a faulty ignition coil. Website: https://www.autozone.com Twitter: / autozone Instagram: / autozone Facebook: / autozone Make sure vehicle is properly secured before performing any automotive work. Wear safety gear as recommended. These videos are intended as an instructional guide for repair. You may encounter slightly different situations with any individual vehicle. Always capture and dispose of or recycle toxic chemicals properly.