Causes for this code may include: Defective HV battery, cell, or battery pack HVBMS sensor failure Individual cell resistance is excessive Discrepancies in cell voltage or temperature HV battery pack fans not working properly Loose, broken, or corroded busbar connectors or cables
This generic powertrain diagnostic trouble code (DTC) typically applies to many OBD-II hybrid electric vehicles. That may include but is not limited to vehicles from Toyota (Prius, Camry), Lexus, Fisker, Ford, Hyundai, GM, etc.
When a code P0A80 is stored, it means that the powertrain control module has detected a malfunction in the hybrid vehicle battery management system (HVBMS). This code indicates that a weak cell failure has occurred in the hybrid battery pack. Hybrid vehicles (which do not require external charging) utilize nickel metal-hydride battery packs. Battery packs are actually blocks of batteries (modules) that are wired together using sections of busbar connectors or cables. The typical HV battery is composed of eight (1.2-volt) cells in series. Twenty-eight modules make up the typical HV battery pack. The HVBMS regulates the charging level of the battery pack and monitors its state. Individual cell resistance, battery voltage, and battery temperature are all factors that are considered by the HVBMS and PCM when determining battery pack condition and the desired charging level. Multiple ammeter sensors and temperature sensors are placed at strategic points throughout the HV battery pack. In most cases, each cell is equipped with a ammeter/temperature sensor. These sensors provide the HVBMS with data from each cell. The HVBMS compares individual voltage signals to determine if inconsistencies are present and reacts accordingly. The HVBMS also provides the PCM with data, via the controller area network (CAN), regarding battery charge level and battery pack condition. When the HVBMS provides the PCM with an input signal which reflects inconsistent battery or cell temperature and/or voltage (resistance), a code P0A80 will be stored and a malfunction indicator lamp may be illuminated.