Telematics Control Module Battery Pack: Notes

The battery pack is located in the telematics control module, under a cover which is retained by a screw.

The battery pack contains one re-chargeable cell and one non-rechargeable cell. The two battery cells are controlled separately by the telematics control module software.

The use of two different battery cells provides continued performance at very low temperatures. The re-chargeable cell cannot deliver the charge effectively at very low temperatures. The non-rechargeable cell has improved performance at low temperatures.

The back-up battery will only be active during an eCall, bCall or stolen vehicle tracking session in which the vehicle power supply is disabled. Once the non-rechargeable cell has been used it will require replacement to restore the full capability of the eCall and stolen vehicle tracking systems.

Telematics control module battery back-up power is also required for the Jaguar logistics tracking system when the vehicle is in transit mode.

Transit mode removes power to the telematics control module approximately 15 seconds after the ignition is switched off (power mode 0). The ignition off mode may occur before the telematics control module has sent all of its logistics tracking data to the manufacturer servers.

The backup battery enables the telematics control module to reliably deliver this data. The telematics control module is programmed not to use the non-rechargeable cell for this purpose.

The telematics control module is in a pre-activated state when in transit mode. The non-rechargeable battery function is not activated as it would become depleted during transportation to the dealer and would immediately require a service replacement before handing the vehicle over to the customer. For this reason only the re-chargeable cell is used in these circumstances.

During the vehicle Pre-Delivery Inspection (PDI) process the TCU is removed from transit mode and switched on to an 'activated state' where both battery cells become active. During a telematics control module main power source dis-connection, the re-chargeable battery cell will always be used first. The non-rechargeable cell is only used if eCall or stolen vehicle tracking are activated.

The expected battery pack life is approximately 10 years if not used frequently. The warranty period of the battery pack may differ between markets.

The telematics control module charges the re-chargeable cell when the engine is running (power mode 7). The charging function is controlled and regulated by the telematics control module software.

• If either battery cell becomes depleted below a preset threshold or fails completely the following warnings/actions are displayed in the message center:
  • SOS System Limited
  • SOS System Not Available.

A signal is sent to the Telematics Service Provider and a Diagnostic Trouble Code (DTC) is set in the telematics control module

When the back-up battery has been replaced, the system must be reset using a specific application on an approved diagnostic system, setting the battery level back to 100%.