Diagnostics based fault tracing procedure

This is applicable when there are DTCs present in the vehicle related to the customer complaint (CSC)

Example: Engine not responding enough when accelerator is depressed. There are DTCs defined in the vehicle to measure engine performance.

Symptom based fault tracing procedure

This is applicable when there are no DTCs defined OR no DTCs are set.

Example: Heavy steering, rattling noise from the back bumper (could be loosened nut or so). It is not possible to have DTCs defined for these kinds of issues.