Battery Monitoring System - Single And Dual Battery System Vehicles: Notes

WARNING: This page is about a different car, the 2015 Jaguar XF, 2014 Jaguar XF, and 2013 Jaguar XF. However, it is still accessible from the selected car via links, so may be relevant.

When the ignition is off (power mode 0), the BMS control module records the primary battery state of charge and begins to monitor the battery condition from this point.

If the battery state of charge falls by 7%, the BMS control module will monitor the primary battery for 5 minutes. If after the 5 minute monitoring period, the primary battery charge has continued to fall due to the quiescent drain current being too high, the BMS control module will determine that some control modules are still 'awake'. The BMS control module sends a shutdown message on the LIN (local interconnect network) bus to the GWM (Gateway Module). The GWM sends a CAN (controller area network) bus message on both the medium and high speed networks to all control modules, requesting them to shutdown.

The BMS control module will monitor the primary battery state of charge for a further 5 minutes and determine if the primary battery state of charge is still dropping. If a quiescent drain current continues, the primary battery state of charge will continue to drop. If the state of charge falls to 12% of the initial monitoring value, the BMS control module determines that one or more control modules are still awake and a failure to respond to the shutdown request may indicate an error state within the control module(s).