Operation CHARM: Car repair manuals for everyone.

Oil Pressure Gauge

The engine oil pressure is displayed by the oil pressure gage. The pointer of the gage is moved by two coils, and its operation is similar to that of the fuel gage.

The oil pressure sensor/switch is connected to the junction of the two coils. It has low resistance when the oil pressure is low, and 90 ohms resistance when the oil pressure is high. This changing resistance changes the current flow through the coils. The magnetic fields of the coils move the pointer from low to high.