DTC P1336: Crankshaft Position System Variation Not Learned: Description

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 PCM. 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 PCM to determine position of TDC cylinder No. 4, necessary to synchronize engine position. PCM must know precisely degree of variability between crankshaft notches in order to correctly perform misfire diagnostics. In order to know this variability, PCM must perform a "crankshaft learn procedure". PCM needs to learn crankshaft variation only once unless a crankshaft or PCM is replaced. DTC sets when PCM has not learned crankshaft notch variation due to PCM replacement or reprogramming when engine is running.