The PPAP must include a PFMEA (Process Failure Mode and Effects Analysis) that considers all the possible failures of the production process for the part in question. When the PFEMA has been created it becomes a living document and is maintained throughout the entire life cycle of the part.
PFMEA evaluates each process step and assigns a score on a scale of 1 to 10 for severity, occurrence, and detection, which then gives you a RPN (Risk Priority Number). The idea of a PFEMA is that it will show you areas in which the production of the part can break down. In turn this can allow you to update the process to make it more robust and understand causes when failure occurs.