DTC P1345: CKP/CMP Correlation: Description
WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The Engine Control Module (ECM) monitors the Crankshaft Position (CKP) and the Camshaft Position (CMP) signals to determine if they are synchronized. If both signals are not observed by the ECM within a narrow time window, the ECM will determine that an error has occurred and DTC P1345 will set.