The special characteristics of products and processes are mentioned in the APQP manual, but KPC and KCC appear in other manuals of AIAG. The English related to these words are as follows:
product special characteristics
process special characteristics
key product characteristics
key control characteristics
KPC is the key product characteristic, and
KCC is the key control characteristic.
product special features = key product features
process special features = key control features
KPC is a product special feature, such as key and important dimensions, which makes the product itself all the features.
KCC is a process control characteristic, such as process parameters of equipment or key and important process parameters.