P050F-01 - Brake Assist Vacuum Too Low - General electrical failure: Action

WARNING: This page is about a different car, the 2017 Jaguar XJ, 2016 Jaguar XJ, 2015 Jaguar XJ, 2014 Jaguar XJ, and 2013 Jaguar XJ. However, it is still accessible from the selected car via links, so may be relevant.

Check brake vacuum is available. Deplete vacuum with engine off until the brake pedal goes hard. With brake pedal still applied start engine, if the pedal drops then vacuum is available
Refer to the applicable SYSTEM WIRING DIAGRAMS and check brake vacuum sensor circuit for open circuit, high resistance
Inspect connectors for signs of water ingress, and pins for damage and/or corrosion
If the brake pedal does not drop check under bonnet for air leaks and brake vacuum pump operation
Check and install a new brake vacuum pump as required
Using the Jaguar Land Rover approved diagnostic equipment, clear the DTCs and retest