Oil Pressure Gauge: Description and Operation

The two-pin oil pressure sensor (B5) in the oil filter (10) converts the engine oil pressure which exists into a resistance. As the oil pressure increases, the resistance increases also. The resistance and engine speed are supplied as input signals to the microprocessor (a) in the electrical base plate of the instrument panel unit (A1).

The microprocessor (a) analyzes the two input signals relative to the stored characteristic curve from an engine speed of > 1200 RPM. Depending on the relevant evaluation. the angle position of the pointer of the oil pressure gauge (A1 p3) is controlled across the scale with the readings 0, 1, 2 and 3.

If the oil pressure drops at a certain engine speed with the result that the resistance drops below a Certain level, the oil pressure pointer moves to the bottom stop (O) and the warning lamp (8) comes on. The oil pressure gauge also moves to the bottom stop (O) in the event of an open circuit in the wiring, but without the warning light (8) being operated.

The oil pressure sensor (B5) is connected to ground at the base plate and to the micro" processor (a) by means of the connector OC27). Voltage is supplied to the base plate through the ignition lock (S2/1). the fuses (5 and 9) in the hose box (F1).