Conditions for Setting the DTC

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT: The ECM detects engine movement by sensing the airflow through the MAF sensor, when airflow is greater than 3 grams per second, or by sensing crankshaft position (CKP) sensor pulses.

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