Control and diagnostic systems for a variable capacity engine oil pump and an engine oil pressure sensor

1. A control system, comprising:

an oil pump module that, based on operating conditions of an engine, selectively generates a first mode request signal to initiate a first transition from operating an oil pump of the engine in one of a first pressure mode and a second pressure mode to operating the oil pump in another one of the first pressure mode and the second pressure mode; and

a diagnostic module that, based on when a driver starts the engine, selectively generates a second mode request signal to initiate consecutive transitions from operating the oil pump in the second pressure mode to operating the oil pump in the first pressure mode, wherein the second pressure mode is different from the first pressure mode and the diagnostic module diagnoses a pump fault when a first oil pressure change associated with the consecutive transitions is less than a first predetermined pressure change.

2. The control system of claim 1 , further comprising a mode selection module that selectively operates the oil pump in the first pressure mode and in the second pressure mode based on the first mode request signal and the second mode request signal.

3. The control system of claim 1 , wherein the diagnostic module selectively determines that the oil pump is stuck in one of the first pressure mode and the second pressure mode based on an engine oil pressure after each of the consecutive transitions.

4. The control system of claim 3 , further comprising:

an oil pressure sensor detecting the engine oil pressure; and

a sensor test module that diagnoses a sensor fault when the engine oil pressure is outside of a predetermined pressure range.

5. The control system of claim 1 , further comprising an active test module that selectively cycles the oil pump a predetermined number of times when the driver starts the engine.

6. The control system of claim 5 , wherein the active test module selectively cycles the oil pump when an engine oil temperature, an engine speed, and an engine torque are within predetermined engine operating ranges.

7. The control system of claim 6 , wherein the active test module refrains from cycling the oil pump when the engine speed is greater than a predetermined speed for a first predetermined period.

8. The control system of claim 6 , wherein the active test module cycles the oil pump when changes in the engine speed and in the engine torque during a second predetermined period are less than predetermined engine operating changes.

9. The control system of claim 6 , further comprising a passive test module that selectively evaluates a second oil pressure change associated with the first transition based on the engine oil temperature and the engine speed.

10. The control system of claim 9 , wherein the passive test module initiates an active test of the oil pump when the second oil pressure change is less than a second predetermined pressure change, wherein the active test module cycles the oil pump when the active test is initiated.

11. A method, comprising:

selectively generating a first mode request signal based on operating conditions of an engine to initiate a first transition from operating an oil pump of the engine in one of a first pressure mode and a second pressure mode to operating the oil pump in another one of the first pressure mode and the second pressure mode;

selectively generating a second mode request signal based on when a driver starts the engine to initiate consecutive transitions from operating the oil pump in the second pressure mode to operating the oil pump in the first pressure mode; and

diagnosing a pump fault when a first oil pressure change associated with the consecutive transitions is less than a first predetermined pressure change, wherein the second pressure mode is different from the first pressure mode.

12. The method of claim 11 , further comprising selectively operating the oil pump in the first pressure mode and in the second pressure mode based on the first mode request signal and the second mode request signal.

13. The method of claim 11 , further comprising selectively determining that the oil pump is stuck in one of the first pressure mode and the second pressure mode based on an engine oil pressure after each of the consecutive transitions.

14. The method of claim 13 , further comprising:

detecting the engine oil pressure; and

diagnosing a sensor fault when the engine oil pressure is outside of a predetermined pressure range.

15. The method of claim 11 , further comprising selectively cycling the oil pump a predetermined number of times when the driver starts the engine.

16. The method of claim 15 , further comprising selectively cycling the oil pump when an engine oil temperature, an engine speed, and an engine torque are within predetermined engine operating ranges.

17. The method of claim 16 , further comprising refraining from cycling the oil pump when the engine speed is greater than a predetermined speed for a first predetermined period.

18. The method of claim 16 , further comprising cycling the oil pump when changes in the engine speed and in the engine torque during a second predetermined period are less than predetermined engine operating changes.

19. The method of claim 16 , further comprising selectively evaluating a second oil pressure change associated with the first transition based on the engine oil temperature and the engine speed.

20. The method of claim 19 , further comprising:

initiating an active test of the oil pump when the second oil pressure change is less than a second predetermined pressure change; and

cycling the oil pump when the active test is initiated.