DTC B12F4-12: Vehicle Speed Output - Circuit short to battery: Action

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2018 Land Rover Range Rover, 2017 Land Rover Range Rover, 2016 Land Rover Range Rover, 2015 Land Rover Range Rover, and 2014 Land Rover Range Rover. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: This DTC refers to a hardwired speed output from the body control module that can be used for aftermarket/accessory fitting where a pulse-width modulation speed signal is required. The circuit is not used on the standard vehicle, but required for aftermarket fitments

Refer to the appropriate system wiring diagrams and check the accessory road speed signal circuit for short circuit to power. Repair the wiring harness as necessary