Audi a4 b8.5 2.0 tdi CJCD low oil pressure warning
I've had the oil pressure sensor replaced twice , and have had the balance shafts / hex key replaced and oil pump replaced all whilst this was done i changed the oil and oil filter but im still having the low oil pressure warning come on when coming to a stop or slowing down at junctions. It's become really puzzling to what it could be , I've read about pcv valves and lifters , but engine sounds perfectly fine and drives well no loss of power or smoke !  🤔 any help or advice would be appreciated many thanks , Gav

Edited August 5, 20241 yr by Gav.81

Welcome Gavin, and thanks for joining.

Having now done what would be considered comprehensive, you now need to get the actual oil pressure physically measured by a garage who has the equipment to do so. This test should be carried out straight after a run of at least 10 miles. Beware that if you leave your car at a garage they are likely to test it just when they can! - and unlikely will have taken it on a run beforehand, so the pressure will be higher than the running actual. 
Having changed what you have, it might not have solved the wear which could have taken place during earlier low oil pressure, so bearings maybe worn. 
Perhaps you could let us know how you get on. 
Kind regards,

Gareth. 

Gavin.

PCV valves are nothing to do with oil pressure. They are involved in crankcase ventilation.

Having renewed the oil pump and pressure switch it is beginning to look like wear in the engine bearings, so the low pressure warning needs to be confirmed as Magnet suggested, before embarking on what could be an expensive repair.