Diagnostic Overview - Engine Oil Pump Solenoid
It is important to note that the Stuck On and Stuck Off diagnostic calibrations are now under one fault code.
The PCM performs multiple diagnostics for the Engine Oil Pump and solenoid. The PCM checks the rationality of the Engine Oil Pressure Sensor before the Oil Pump Solenoid diagnostic runs. Typically a faulty EOP Sensor will set a fault and disable the Oil Pump Solenoid diagnostic.
- During higher engine speeds the PCM commands the Oil Pump Solenoid a higher duty cycle. The PCM monitors the engine oil pressure and fails when the pressure is below a calibrated threshold.
- At idle, or lower engine speeds the PCM commands the Oil Pump Solenoid a lower duty cycle. The PCM monitors the engine oil pressure and fails when the pressure is above a calibrated threshold.
Component or system rationality diagnostics are typically designed to detect a mechanical failure in the component (solenoid, motor, actuator) or overall system performance issue. A circuit fault against a component or sensor being used to monitor the system should be diagnosed before a rationality fault. However, do not assume that the wiring or circuits are good if you do not have a circuit fault. In some circumstances a circuit issue could also cause a rationality fault to set without a circuit fault. Rationality faults are designed to catch any failure that could be missed in other diagnostics. An example could be a small amount of resistance in the power supply, control or ground circuit to a component, usually at the harness connector terminals, that could cause a component not to energize when commanded on. In many cases a few ohms of resistance at a connector may not cause a circuit fault to set. It is always a good practice to learn and understand how the rationality checks are performed and the faults are detected. Then check the connectors and circuits for the wiring conditions that could cause that failure mode (open or shorted circuit) before replacing any components.