The PDP and PCM do not affect each other like that. In other words the PDP does not prevent the PCM to enable compressor output through software (although the PDP does power PCM, the PCM is clearly running since it self-tested).
Please follow the instructions in section 4.1 in PCM User's Manual to get the compressor working.
http://www.ctr-electronics.com/contr...ical_resources.