Understanding the appropriate procedure and diagnosis codes for a particular study question is an important part of analyzing Medicare data. These codes are very specific and can change from year to year as new codes are added and others are discontinued.
There is no wear-out factor in the coil itself other than thermal cycling and the damage it may cause. Boots and wires do age, resulting in reduced insulation value over time. The key to correct ignition system diagnosis is to understand the details of how the system you are working on really functions. PAGE:
How to Test for a Faulty Coil. A quick way to test for a faulty coil is to allow the vehicle for run for about 30 minutes and then gently rap the module with the head of a screwdriver. If the car engine dies, this is a good indicator that the ignition coil is faulty and needs to be replaced.