Engine oil
 

When checking engine oil on instruments at my XF 5.0 it writes engine failure. Do you just renew the oil presure swich, or anything else ??

Get a code reader and see what the ECU says about "engine failure"

That sounds really bad.

Engine oil
 

when testing with engine tester the message came out b100a and in an reference it said Number-plate- right sid fault. I knew that and had ignored it as an minor fault to be repaired next service. But anyway I fitted an new light and now I can measure the engine oil. Strange that these two faults is connected.

Good job getting a code reader. When getting an error on the dash, it's always the first step before anything else, including posting to forums.