Synchronization diagnostic systems and methods for engine controllers

1. An engine controller diagnostic system comprising:

a cylinder identification (ID) comparison module that compares a first cylinder ID associated with a first controller with a second cylinder ID associated with a second controller;

a plurality of engine diagnostic modules that comprise a camshaft position sensor diagnostic module, an ignition system diagnostic module, an exhaust monitoring module, a fuel rail pressure monitoring module, and a fuel iniector diagnostic module; and

a synchronization diagnostic module that determines a synchronization status of the first controller based on (i) a comparison between the first cylinder ID and the second cylinder ID and (ii) at least one signal from at least one of the plurality of engine diagnostic modules,

wherein the synchronization diagnostic module determines that the first controller is correctly synchronized when the first cylinder ID and the second cylinder ID are out of phase with each other and the at least one signal indicates no faults in engine components associated with the plurality of engine diagnostic modules.

2. The engine controller diagnostic system of claim 1 wherein the exhaust monitoring module generates the at least one signal when an oxygen concentration of an exhaust gas exceeds a threshold.

3. The engine controller diagnostic system of claim 1 wherein the fuel rail pressure monitoring module generates the at least one signal when a fuel rail pressure is outside a predetermined range.

4. The engine controller diagnostic system of claim 1 further comprising a cylinder ID counter associated with the first controller, wherein the cylinder ID counter increments the first cylinder ID when the synchronization diagnostic module determines that the first controller is not correctly synchronized.

5. The engine controller diagnostic system of claim 4 wherein the cylinder ID counter increments the first cylinder ID by a value equal to a total number of cylinders over 2.

6. The engine controller diagnostic system of claim 1 wherein at least one of a fuel injector and a spark plug is disabled when at least one of the ignition system diagnostic module and the fuel injector diagnostic module diagnoses a fault in the at least one of the fuel injector and the spark plug.

7. The engine controller diagnostic system of claim 1 wherein the synchronization diagnostic module determines that the first controller is correctly synchronized when the first cylinder ID and the second cylinder ID are in phase with each other.

8. A method of diagnosing an engine controller comprising:

comparing a first cylinder identification (ID) associated with a first controller and a second cylinder ID associated with a second controller; and

determining a synchronization status of the first controller based on (i) a comparison between the first cylinder ID and the second cylinder ID and (ii) at least one signal from at least one of a plurality of engine diagnostic modules that comprise a camshaft position sensor diagnostic module, an ignition system diagnostic module, an exhaust monitoring module, a rail pressure monitoring module, and a fuel injector diagnostic module,

wherein the first controller is correctly synchronized when the first cylinder ID and the second cylinder ID are out of phase with each other and the at least one signal indicates no faults in engine components associated with the plurality of engine diagnostic modules.

9. The method of claim 8 wherein the exhaust monitoring module generates the at least one signal when an oxygen concentration of an exhaust gas exceeds a threshold.

10. The method of claim 8 wherein the rail pressure monitoring module generates the at least one signal when a rail pressure is outside a predetermined range.

11. The method of claim 8 further comprising incrementing the first cylinder ID when the first controller is not correctly synchronized.

12. The method of claim 11 further comprising incrementing the first cylinder ID by a value equal to a total number of cylinders over 2.

13. A control system for an engine, the control system comprising:

a first control module that controls N cylinders of the engine, wherein the engine includes M cylinders, wherein N is an integer greater than zero, and wherein M is an integer greater than N;

a second control module that controls (M-N) cylinders of the engine; and

a synchronization module that determines whether the first and second control modules are synchronized based on (i) camshaft position and (ii) crankshaft position.

14. The control system of claim 13 , wherein the synchronization module determines first and second cylinder identifications (IDs) based on the camshaft position and crankshaft position, wherein the first and second cylinder IDs indicate next cylinders in a firing order of the N and (M-N) cylinders, respectively, and wherein the synchronization module determines whether the first and second control modules are synchronized based on a phase relationship between the first and second cylinder IDs.

15. The control system of claim 13 , wherein the synchronization module determines whether the first and second control modules are synchronized further based on first and second exhaust gas oxygen concentrations, wherein the first and second oxygen gas concentrations correspond to exhaust gases produced by the N and (M-N) cylinders, respectively.

16. The control system of claim 13 , wherein the synchronization module determines whether the first and second control modules are synchronized further based on first and second fuel rail pressures, wherein the first and second fuel rail pressures correspond to fuel rails associated with the N and (M-N) cylinders, respectively.

17. The control system of claim 13 , wherein the synchronization module increments a cylinder identification (ID) counter when the first and second control modules are determined not to be synchronized.

18. The control system of claim 17 , wherein the synchronization module compares the cylinder ID counter to a predetermined threshold, wherein the synchronization module increments a cylinder ID of the first control module when the cylinder ID counter is less than or equal to the predetermined threshold, and wherein the cylinder ID indicates a next cylinder in a firing order of the N cylinders associated with the first control module.

19. The control system of claim 18 , wherein the synchronization module increments the cylinder ID by M/2.

20. The control system of claim 13 , wherein N equals M/2.