Faulty Hybrid/EV Battery Pack
Hybrid/EV Battery Pack harness is open or shorted
Hybrid/EV Battery Pack circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
The Battery Energy Control Module will diagnose its own systems and determine when a fault condition is present. Diagnostics and system status is communicated from the battery energy control module to the vehicle control interface module through serial data. The vehicle control interface module is the host controller for Diagnostic Trouble Code (DTC) information.
The vehicle is equipped with a high voltage isolation monitor feature. The purpose of the high voltage isolation circuit is to test the resistance between the high voltage positive and negative direct current (DC) bus and chassis ground. The battery energy control module only runs this test when the ignition transitions from ON to OFF and the high voltage contactor relays have opened. The battery energy control module has an internal isolation sensor that measures the resistance between the high voltage DC positive and negative bus and chassis ground. The battery energy control module runs an internal self check of this sensor circuit. The battery energy control module sends an AC signal over the DC bus and monitors its amplitude. A low amplitude or collapsed return signal indicates a loss of resistance to chassis ground and a loss of isolation will be indicated by the hybrid powertrain control module 2. Because this diagnostic runs after system power down, the diagnostic status does not get reported until the next key cycle.