This paper investigates the impact on the power saving mechanism (PSM) of the cellular digital packet data (CDPD) caused by random frame errors and losses. To combat such random frame errors and losses, a selective repeat (SR) protocol of automatic repeat request (ARQ) protocols in charge of recovery of garbled/lost frames is combined with the original PSM of CDPD and then study the enhanced PSM and investigate the effect of channel conditions including bit error rate and frame loss probability as well as frame buffer size and window size of SR-ARQ to the PSM through numerical examples. The results provided in this paper are able to serve as guidelines on system design and parameter setting for CDPD when an imperfect channel is taken into consideration to reflect the realistic situation.