Component Functional Description - Oil Pump Solenoid

The mechanical Engine Oil Pump operates in two pressure modes described below. The Powertrain Control Module (PCM) switches the pump between modes based on the oil temperature, coolant temperature, and engine operating conditions.

Low Mode: To operate the pump in low pressure mode the PCM commands the High Side Driver (HSD) control on, energizing the Oil Pump Solenoid. The Engine Oil Pump is operated in low pressure mode between idle and approximately 3000 RPM.
High Mode: To operate the pump in high pressure mode the PCM commands the HSD control off, de-energizing the Oil Pump Solenoid. The PCM will typically switch the pump from low to high mode when the engine speed increases over approximately 3000 RPM.
In some instances the system can change to high pressure mode before the engine speed listed when the PCM detects that the engine load increases above a calibrated threshold. This can sometimes be determined by monitoring the oil pressure reading. Typically pressure will increase in relation to engine speed. When the system changes modes the pressure may increase suddenly up or down depending on which mode is being commanded.

NOTE:

The specifications are different between the classic and upgrade 3.6L engines. Choose the appropriated specification chart for the vehicle being diagnosed.

See the oil pressure specifications in the tables below:

3.6L CLASSIC ENGINES - OIL PRESSURE SPECIFICATIONS
ENGINE SPEED	OIL PUMP MODE	OIL PRESSURE SPECIFICATION
Idle (650 RPM)	Low Pressure Mode (Solenoid on)	Above 82.7 kPa (Above 12 psi)
1000 - 3000 rpm	Low Pressure Mode (Solenoid on)	200 - 358.5 kPa (29 - 52 psi)
Above 3500 RPM	High Pressure Mode (Solenoid off)	413.7 - 689.5 kPa (60 - 100 psi)
NOTE 1: Values in the table are valid for coolant temperature between 89 - 100°C. NOTE 2: For Idle (650 RPM approximately) - If vehicle coolant temperature is under 100°C, it is possible to have the pump working in High pressure mode (solenoid off) and pressure readings above 34 PSI.

3.6L UPGRADE ENGINES - OIL PRESSURE SPECIFICATIONS
ENGINE SPEED	OIL PUMP MODE	OIL PRESSURE SPECIFICATION
Idle (650 RPM)	Low Pressure Mode (Solenoid on)	103.4 - 234.4 kPa (15 - 34 psi)
1000 - 3000 rpm	Low Pressure Mode (Solenoid on)	193 - 241.3 kPa (28 - 35 psi)
Above 3500 RPM	High Pressure Mode (Solenoid off)	448.2 - 551.6 kPa (65 - 80 psi)
NOTE: Values in the table are valid for coolant temperature between 89 - 100°C.