N172130461 (18216) - Customer Satisfaction Program - Certain 2011 model year Chevrolet Volt vehicles equipped with a high voltage battery, may have a condition where it could gradually lose the ability to maintain voltage. If battery concerns are not addressed, over time the vehicle could enter a reduced propulsion mode while driving, or lose propulsion, or it may not start. Dealers are to update the Hybrid Powertrain Control Module 2 (HPCM2). This software update is intended to increase the amount of warning time provided.
