Three step cam defaulting strategy for engine position sensors

A method for operating a camshaft system for an internal combustion engine, the method comprising:

• providing an internal combustion engine having a controller, a crankshaft position sensor, and a camshaft system having a first camshaft barrel slidingly disposed on a camshaft, the camshaft barrel having a high lift lobe for operating in a high lift mode, a low lift lobe for operating in a low lift mode, an AFM lobe for operating in an AFM mode, and a slot;
• receiving a fault condition indication from the crankshaft position sensor;
• determining which of the high lift mode, the low lift mode, and the AFM mode the internal combustion engine is operating;
• and
• ceasing to command a mode change from the controller to the internal combustion engine when the internal combustion engine is operating in one of the high lift mode and the low lift mode.

A method for operating a camshaft system for an internal combustion engine, the method comprising:

• providing an internal combustion engine having a controller, a crankshaft position sensor, and a camshaft system having a first camshaft barrel slidingly disposed on a camshaft, the first camshaft barrel having a high lift lobe for operating in a high lift mode, a low lift lobe for operating in a low lift mode, an AFM lobe for operating in an AFM mode, and a slot;
• receiving a fault condition indication from the crankshaft position sensor;
• determining which of the high lift mode, the low lift mode, and the AFM mode the internal combustion engine is operating;
• ceasing to command a mode changes from the controller to the internal combustion engine when the internal combustion engine is operating in one of the high lift mode and the low lift mode;
• and
• commanding the camshaft system to operate in the low lift mode when the internal combustion engine is operating in the AFM mode.