2012 Audi A6L C7 oil warning light on

Car model: 2012 Audi A6L C7
Engine: CLX engine
Transmission: 0AW automatic transmission
Mileage: 50,000 km
Trouble syndrome: Oil warning light is on

Preliminary diagnoses: I use VAS 5054A to troubleshoot the cars ECU and got a fault code P164D, which indicates to Oil Pressure Switch for reduced Oil Pressure:

Malfunction. I erased the fault code with the VW diagnostic tool and then test the cars oil pressure, which is 60kPa at idle, obviously far less than the normal 120kPa pressure. Then I search for the reason of less oil pressure based on the oil pump working principle, and find out a loosen pressure-limiting valve as shown below.

Preliminary analysis: I ask the driver if he had taken the car to maintenance recently, and he told me that the oil filter in the car was replaced recently. Hence, I am almost sure that the light comes up because the oil line was blocked by the badly installed pressure-limiting valve.

Solution: I remove the pressure-limiting valve and reinstall it immediately, and the oil warning light then goes out soon.

Article resource:http://www.eobd2.fr/service/2012-audi-a6l-c7-avertissement-de-lhuile-lgre-sur-7605.html