The ignition coil is an essential part of the ignition of a vehicle. Each coil is used for one or two engine cylinders and so therefore there are several ignition coils in the ignition system. Each coil’s role is to transfer the power from the vehicles 12volt battery in to a much higher voltage of thousands of volts to create the spark in spark plugs. They are then told when to fire by an on-board computer. These coils have some form of resistor in them, which limits the amount of power transmitted to the coils from the 12volt battery.
Should a ignition coil fail, it is possible that this can cause its adjoined engine cylinder to misfire. This is the case even if all of the other coils are working correctly. Damage to the ignition coil may show on the dashboard as a ‘check engine’ light. Damage can be caused by worn spark plugs, which make the ignition coil work harder to compensate, or faulty wiring or components. The coils can also simply wear out through repeated use.