What should be done during an ignition functional timing test of a coil on plug ignition system?

In a coil-on-plug ignition system, the ignition timing is typically preset and not designed to be adjusted. During an ignition functional timing test, the primary function is to verify that the system is functioning properly and has the correct timing. Since the system does not allow for adjustments like traditional timing setups, it’s important to document that it is not adjustable. This documentation helps ensure accurate records and informs future testing and inspections that this system does not require timing adjustments.

Adjusting the timing is not relevant to coil-on-plug systems, as they are designed for fixed timing operations. Changing the spark plugs is also separate from timing; while it's important for maintenance, it does not relate to the timing test itself. Running a diagnostic test can be a part of initial troubleshooting, but it does not directly address the action of confirming that the ignition timing is not adjustable for this type of ignition system. Thus, documenting the non-adjustability of the timing is the appropriate and correct action during this test.