Primary torque actuator control systems and methods

1. An engine control system comprising:

a coordinated torque control module that determines a first position for a throttle valve of a spark-ignition internal combustion engine and that controls opening of the throttle valve based on the first position;

a diagnostic module that selectively diagnoses an engine shutdown fault and that disables the control of the opening of the throttle valve based on the first position when the engine shutdown fault is diagnosed; and

an actuator limiting module that, in response to the diagnosis of the engine shutdown fault:

determines a second position for the throttle valve based on an accelerator pedal position;

selects a lesser one of the first and second positions; and

selectively limits the opening of the throttle valve to the lesser one of the first and second positions to allow engine operation to continue.

2. The engine control system of claim 1 wherein the actuator limiting module determines the second position further based on a brake pedal position.

3. The engine control system of claim 2 wherein the actuator limiting module shuts down the engine when a fault is present in a throttle actuator module when the engine shutdown fault is diagnosed.

4. The engine control system of claim 1 wherein the actuator limiting module limits the second position to a predetermined idle position when the accelerator pedal position is less than a predetermined minimum accelerator pedal position.

5. The engine control system of claim 1 wherein the actuator limiting module limits the second position to a predetermined maximum position when the accelerator pedal position is greater than a predetermined maximum accelerator pedal position.

6. The engine control system of claim 1 wherein the actuator limiting module limits the second position to a predetermined idle position when the accelerator pedal position is less than a first predetermined accelerator pedal position and limits the second position to a predetermined maximum position when the accelerator pedal position is greater than a second predetermined accelerator pedal position.

7. The engine control system of claim 6 wherein the actuator limiting limits the second position to the predetermined idle position when a brake pedal position is greater than a zero brake pedal position.

8. The engine control system of claim 7 wherein the actuator limiting module limits the second position to the predetermined idle position when the brake pedal position is greater than a zero brake pedal position and the accelerator pedal position is greater than the first predetermined accelerator pedal position.

9. The engine control system of claim 1 wherein the coordinated torque control module further determines a first parameter based on one or more inputs and one or more relationships that relate the one or more inputs to the first parameter, and

wherein the diagnostic module determines a second parameter that corresponds to the first parameter based on the one or more inputs and diagnoses the fault based on a comparison of the first parameter and the second parameter.

10. The engine control system of claim 1 wherein the coordinated torque control module further stores values in two different locations in memory, and

wherein the diagnostic module reads the values and diagnoses the fault based on at least one of a comparison of the values and a comparison of the values with expected values.

11. An engine control system comprising:

a coordinated torque control module that determines a first fueling amount for a compression-ignition internal combustion engine and that controls provision of fuel to the engine based on the first fueling amount;

a diagnostic module that selectively diagnoses an engine shutdown fault and that disables the control of the provision of fuel based on the first fueling amount when the engine shutdown fault is diagnosed; and

an actuator limiting module that, in response to the diagnosis of the engine shutdown fault:

determines a second fueling amount for the engine based on an accelerator pedal position;

selects a lesser one of the first and second fueling amounts; and

selectively limits the provision of fuel to the engine to the lesser one of the first and second fueling amounts to allow engine operation to continue.

12. The engine control system of claim 11 wherein the actuator limiting module determines the second fueling amount further based on a brake pedal position.

13. The engine control system of claim 12 wherein the actuator limiting module shuts down the engine when a fault is present in a fuel actuator module when the engine shutdown fault is diagnosed.

14. The engine control system of claim 11 wherein the actuator limiting module limits the second fuel amount to a predetermined idle fuel amount when the accelerator pedal position is less than a predetermined minimum accelerator pedal position.

15. The engine control system of claim 11 wherein the actuator limiting module limits the second fuel amount to a predetermined maximum fuel amount when the accelerator pedal position is greater than a predetermined maximum accelerator pedal position.

16. The engine control system of claim 11 wherein the actuator limiting module limits the second fuel amount to a predetermined idle fuel amount when the accelerator pedal position is less than a first predetermined accelerator pedal position and limits the second fuel amount to a predetermined maximum fuel amount when the accelerator pedal position is greater than a second predetermined accelerator pedal position.

17. The engine control system of claim 16 wherein the actuator limiting limits the second fuel amount to the predetermined idle fuel amount when a brake pedal position is greater than a zero brake pedal position.

18. The engine control system of claim 17 wherein the actuator limiting module limits the second fuel amount to the predetermined idle fuel amount when the brake pedal position is greater than a zero brake pedal position and the accelerator pedal position is greater than the first predetermined accelerator pedal position.

19. The engine control system of claim 11 wherein the actuator limiting module determines the second fuel amount further based on an engine oil temperature.

20. The engine control system of claim 19 wherein the actuator limiting module increases the second fuel amount as the engine oil temperature decreases and decreases the second fuel amount as the engine oil temperature increases.