Battery And Cables: Overview: Notes

WARNING: This page is about a different car, the 2020 Jaguar XE and 2019 Jaguar XE. However, it is still accessible from the selected car via links, so may be relevant.

The battery is positioned in the luggage compartment floor and is secured in position with a clamp plate. The battery supplies electrical power to the Battery Junction Box (BJB). The BJB contains megafuses, delivering power to the starter motor and the generator, the Rear Junction Box (RJB), the Passenger Junction Box (PJB), and the left and right Engine Junction Box (EJB).

Three different type of battery is used, depending on the following:

Vehicles without Telematics Control Module (TCU) and Fuel Fired Booster Heater (FFBH) - 70Ah, 760CCA Absorbed Glass Mat (AGM) Valve Regulated Lead-Acid (VRLA) battery
Vehicles without FFBH, with TCU - 80 Ah, 800 CCA AGM VRLA battery
Vehicles with FFBH - 90 Ah, 850 CCA AGM VRLA battery
Cold market vehicles - 90 Ah, 850 CCA AGM VRLA battery

A Battery Monitoring System (BMS) control module is mounted on the battery negative terminal and provides battery status information for the Body Control Module/Gateway Module (BCM/GWM) assembly.

CAUTION: When connecting a slave power supply to the vehicle, to avoid damaging the BMS control module, always use the ground (negative (-)) terminal stud point on the right side top mount in the engine compartment. Never connect directly to the battery negative terminal when connecting a slave power supply to the vehicle; the BMS control module can be damaged.

The BJB is located below the luggage compartment floor panel, adjacent to the battery. The RJB is located on the right side of the luggage compartment behind the trim panel. The BJB and RJB contain fusible links, fuses, and relays to distribute electrical power to various vehicle systems. The right and left EJBs are mounted adjacent to the appropriate front suspension top mount in the engine compartment.

A jump start terminal is located below a hinged cover, adjacent to the right EJB. An additional cover with a lanyard protects the terminal when not in use. If jump starting is required, the cover must be removed and the positive (+) jump lead attached securely. The negative (-) jump lead is attached to a jump start terminal stud located on the right side top mount. The cover must be fitted to the positive terminal when not in use.

The Voltage Quality Module (VQM) is used to prevent the vehicle electrical systems being subjected to undesirably low voltages during repeated engine restarts and produces a constant output voltage during engine restart operation. If the electrical systems are subject to low voltages the customer may notice degraded performance of components and systems and incorrect fault Diagnostic Trouble Code (DTC) may be stored.

The PJB is located behind the A-pillar lower trim panel on the passenger side and receives its main power supply from the BJB.

The BCM/GWM assembly is located adjacent to the PJB, and it is the main controller of the vehicle body systems. The BCM/GWM assembly controlled functions are outlined in the relevant articles.

The BCM/GWM assembly software will monitor the state of charge of the battery and will determine when a stop/start event can occur. It can also intervene to maintain vehicle systems by keeping the engine running or initiating a restart due to, for example, climate control system requirements or request for restart from the Engine Control Module (ECM). A brake pressure signal is received from the ECM which will indicate to the BCM/GWM assembly that an engine restart is required from driver operation of the foot brake. For additional information, refer to:

Starting System (INGENIUM I4 2.0L Diesel, Description and Operation),

and Starting System (V6 S/C 3.0L Petrol, Description and Operation).