Oil Pressure Sensor: Description and Operation

Engine Oil Pressure (EOP) Switch:

The Engine Oil Pressure (EOP) switch is located in the front of the engine block near the starter motor. The EOP switch is a normally closed switch that opens when engine oil pressure exceeds 3.6+/-2.2 psi. The ECM supplies ignition voltage through a resistor to the EOP switch. With ignition On, engine Off, the ECM EOP input will be low (near 0 volts, switch closed). When the engine is started, and engine oil pressure exceeds 3.6+/-2.2 psi, the switch opens and the ECM EOP input goes high (ignition voltage).