Conditions for Setting the DTC

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The ECM detects that the starter is commanded on and the engine has been cranking for greater than 4 s without a camshaft position sensor pulse.
The ECM detects that the engine has started, but did not receive a camshaft position sensor pulse during the first engine revolution.
The ECM detects that the engine is running, but does not receive a camshaft position sensor pulse for 800 of 1000 engine cycles.