Here is the CPS on an M113 V8 , same on the V6 version and many others. Counts the pulses from the starter motor ring (kind of) which , of course, is bolted directly to the crankshaft.
Is it perhaps the camshaft sensor you are looking for ?
A "P0016" fault code on a Mercedes indicates a problem with the correlation between the crankshaft position and the camshaft position, essentially meaning the timing of the engine is out of sync, often caused by a faulty camshaft position sensor, a worn timing chain, or issues with the crankshaft position sensor itself.