Hybrid Powertrain Control Module (HPCM): Location
WARNING: This page is about a different car, the 2009 GMC Yukon, 2009 Chevrolet Tahoe, and 2009 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.
The HPCM is a non-serviceable, flash-programmable micro-processor contained within the PIM assembly.