Faulty Battery Energy Control Module
Battery Energy Control Module harness is open or shorted
Battery Energy Control Module circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
The hybrid battery pack contains a total of 32 cell groups in the hybrid/EV battery pack assembly. These cell groups are electrically connected in series. Each individual cell group is rated at 3.7 V, for a nominal system voltage of 118 V DC. The battery cells are grouped together into two sections, each with 16 cell groups.
The battery energy control module monitors the voltage of the 32 battery cell groups. A voltage sense circuit is attached to each individual cell group. Each of these circuits terminate at a connector located on the top surface of the battery section. A serviceable auxiliary battery wiring harness connectors the voltage sense circuits to the battery energy control module, located directly above the hybrid battery pack.
To ensure proper battery function and lengthen battery life, the battery energy control module balances the voltage of the cells so that each cells maintains the same voltage level. The battery energy control module uses internal voltage gates to transfer voltage from cells with a higher voltage level to those cells with a lower voltage level. To maintain a similar state of charge on the cell groups, the starter/generator control module monitors the cell voltages and determines which cells need energy removed in order to maintain the cells at a similar state of charge. A resistor wired in parallel with the cell and a transistor switch in series with the resistor internal to the battery energy control module. The starter/generator control module sends a command to the battery energy control module to begin cell balancing.