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Ok so customer Audi he put 6 litres of oil in the engine after seeing a low oil level message and stop engine on his dashboard. The message was wrong. He had a new Audi oil temp sensor which is a variable resistor installed and nothing. Still behind steering wheel in odometer it says low engine oil stop immediately. The centre of the dash however is another screen which says cannot communicate with oil temp sensor.
Have checked power and ground wires to sensor. Then using Fluke 88v automotive multimeter checked signal wire. It shows there are figures between 200 and 800. jumping in number by a hundred each time and about twice a second or three times a second. to fast for the eye to catch but in my iPhone on slow mo, I could see the numbers. So checked the same signal wire where it went into the ECM and same kinda numbers there too. So presume the wire integrity of signal wire ok. A guy on Youtube says the ECM looks at the hood catch and then when the catch changes from closed to open for more than 2 minutes, the ECM checks the oil level. I dont think this is true. The hood switch is power one side and ground the other. ECM power to switch and then ground as it engages. The switch is a micro switch. However when the hood is opened or closed the customer every time I did it said he could see the hood open and closed symbol on his odometer/speedo. So the switch obviously works.
On Monday I shall try using my Autel MS906 scan tool to force oil reset. Failing that I do not know the answer. Does anyone else know...?
Oil temp sensor and oil level sensor are two different components/sensors as well as oil pressure sensor and oil pressure switch.
Oil level sensor is attached to the side of oil pan and has two wires going to it.
Oil temp sensor can vary in location but typically attached near oil filter boss or near oil cooler.
Oil pressure sensor would be near oil filter boss or threaded into a oil galley hole.
Oil pressure switch in similar locations to oil pressure sensor but only say to the ECM there is pressure or there is no pressure.
Make sure about the correct part definition as you can see they are very different. I also think you did not replace the correct part. You will also want to check wiring as wiring issues are more typical for under the car due to hitting road debris or furry wire hungry monsters.
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