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audi q5 oil pressure sensor replacement
When should audi q5 oil pressure sensor replacement: Fault diagnosis: the fault code "P164D00: oil pressure switch for lower oil pressure - function failure" is stored in the engine control unit when the fault detector is used for detection; Read the status of the low pressure switch (F378). It is found that the status of F378 is always "open" when idling, which is abnormal. F378 is a pair of normally open contacts, which is used to monitor whether the oil pressure is established. Normally, the normally open contact of F378 is closed under the action of oil pressure when idling, that is, the status changes from "open" to "closed". The analysis shows that the possible causes of abnormal state of F378 are: low oil pressure; F387 and its circuit are faulty. Line F387 is measured and no abnormality is found; Remove F387 and measure the oil pressure with the oil pressure detection equipment (VAG 1342).
The oil pressure at idle speed is about 0.8 bar (1 bar=100 kPa), which is lower than the standard value (0.85 bar~1.6 bar); When the engine speed is about 2000 r/min, the oil pressure is about 1.6 bar, which is normal (the standard value is 1.2 bar-1.6 bar). At the same time, it is found that the status of F378 changes from "open" to "closed". It can be inferred that the failure of the vehicle is caused by the low oil pressure at idle speed. The possible causes of the failure are: the oil pump is damaged; The oil filter is damaged or blocked; The pressure rod of oil filter base is damaged or deformed; Pressure relief of piston cooling injector control valve (N522) (mechanical switch valve stuck); The internal components of the engine (camshaft, crankshaft, bearing, etc.) are abnormally worn. When the engine is idling, N522 is connected, the mechanical switch valve closes the pipeline to the oil passage of the piston cooling injector, and the oil pressure switch (F447) of the piston cooling injector is "open" (F447 is closed when the oil pressure of 0.3 bar-0.6 bar is detected), that is, no oil pressure is detected, which indicates that N522 does not have pressure relief. Check whether the oil filter and oil filter base pressure bar are normal; Try to replace the oil pump and run the engine, the red oil pressure alarm lamp is still on.
Based on the principle of "from simple to complex", remove the camshaft bearing bridge first, observe the camshaft journal, and find that there is obvious wear at the radial contact position between the camshaft on the intake side and the bearing bridge. Troubleshooting: replace the intake camshaft, matching three-way four-way valve and bearing bridge bracket, and then conduct a test run. The red engine oil pressure alarm lamp will no longer light up; Measure the oil pressure at idle speed, which is about 1.5 bar. The oil pressure returns to normal and the fault is eliminated.
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