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 PCM supplies ignition voltage through a resistor to the EOP switch. With ignition On, engine Off, the PCM EOP input will be low (near 0 volts, switch dosed). When the engine is started, and engine oil pressure exceeds 3.6 ± 2.2 psi, the switch opens and the PCM EOP input goes high (ignition voltage).


OIL PRESSURE TELLTALE
The PCM sends a message to the I/P cluster over the Class II link to turn On the Oil Pressure telltale whenever the ignition is On and the EOP input at the PCM is low.