Conditions for Setting the DTC

WARNING: This page is about a different car, the 2010 GMC Sierra and 2010 Chevrolet Silverado. 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 more than 4 s without a crankshaft position sensor pulse.
The ECM detects that the engine is running, but has not received a crankshaft position sensor pulse for 2 of 10 engine cycles.