DTC P1336: Crankshaft Position System Variation Not Learned: Description

WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Crankshaft Position (CKP) sensor produces an AC voltage of different amplitude and frequency depending on velocity of crankshaft. This AC voltage signal is fed into EI module, which is converted to a square wave, 0-5 volts, and then sent to ECM. Crankshaft has 7 total machined notches, 6 of which are spaced 60 degrees apart. Remaining tooth is 10 degrees before cylinder No. 4 TDC notch. This extra notch is used by ECM to determine position of TDC cylinder No. 4, necessary to synchronize engine position. ECM must know precisely degree of variability between crankshaft notches in order to correctly perform misfire diagnostics. In order to know this variability, ECM must perform a "crankshaft learn procedure". ECM needs to learn crankshaft variation only once unless a crankshaft or ECM is replaced. DTC sets when ECM has not learned crankshaft notch variation due to ECM replacement or reprogramming when engine is running.