Oil Pressure Sensor: Description and Operation

Schematic:

The oil pressure switch is located in engine block near oil filter cartridge housing. The switch is closed with low engine oil pressure. The switch will be closed with engine not running. When switch is closed input at PCM will be low (zero volts). The PCM sends a class II message to I/P cluster to turn On the Low Oil Pressure Telltale. The switch opens with normal engine oil pressure. When switch opens PCM input will be high (ignition voltage). The PCM will command Low Oil Pressure telltale Off.