Audi A6L 2.0T oil level indicator not working

Today I fixed a 2009 Audi A6L 2.0T, which had done 120,000 miles on it. The car was equipped with a B PJ engine, and a 01) transmission. The driver told me that there was something wrong with its oil level indicator as the gauge was not accurate.
Premilinary inspection: The oil indicator advised the driver to add 1 litre of oil, but the driver said he just added half tank of fuel, which meant the oil should be actually enough. I used a Tuirel S777 diagnostic tool to read the OBDII system, and there was no DTCs stored in the system. Then I went on a component testing. The oil level then could successfully restore, which indicated problem in oil level sensor or related circuits. I pulled off the fuel pump connector and tested the voltage in the sensor. The voltage was within the normal range.
I removed the oil pump and moved the floater to test its resistance. According to ELSA Submission Standards, the resistance betwwen oil level sensor and its bond should be 900Ω in empty oil tank and 50Ω in full oil tank. But the result I got was different from these two numbers. It was probably that the floater was damaged.
Trouble removal: I replaced the oil pump assembly, and the oil level indicator could work alright then.