Installation of an ignition coil would always address the problem of a flashing check engine light due to a misfire in an idealistic situation. If this were the case, there would be no need for part returns. As it turns out, a misfire can be caused by more than just a lack of spark from the ignition coil directly.
Ignition coils come in assorted sizes and colors, but they always have three components in common. Primary windings, secondary windings, and a non-conductive or dielectric insulation material that separates the two windings are all included. The insulation is usually a dielectric resin that is placed in a vacuum to avoid the formation of air bubbles. Air bubbles may provide a channel for electricity to go through a coil, causing it to fail prematurely.
Heat, vibration, or issues on the secondary side of the ignition system may all cause coil failure. Ignition coils are often attached to the cylinder head, either on top of or inside of a cylinder-specific well. High heat and vibration may break down the insulating material, causing internal coil breakdown. Worn secondary ignition elements like spark plugs or wires may make a coil work harder, requiring higher voltage and shortening the coil's life.
Electricity may not be able to reach its intended destination due to a faulty coil. When this occurs, the electricity generated within the secondary windings seeks the channel to the ground with the least amount of resistance. This route is most frequently seen in the coil's boot or body. When oil, dust, or moisture is electrostatically bonded to the boot or insulator and provides a channel to the ground, carbon tracking occurs. The coil and associated plug must be changed if carbon tracking is identified. It is also feasible that a faulty ignition coil may harm the engine computer, commonly known as the ignition control module.
Replacement ignition coils are often designed to avoid the pattern failures that plague original ignition coils. Improved dielectric materials that properly insulate the secondary and main coils are one example of these enhancements. Furthermore, the design of the ignition control module may be improved so that it can withstand higher levels of temperature and vibration.
The customer at the counter should inquire if a coil has been returned and for what reason it is being sent back. Because the coils are checked before the unit is packed in the box, production faults for coils are incredibly low to non-existent for some vendors.