Use start behavior, RPM data, companion codes, and timing clues to separate a true cam-crank correlation problem from a missing crank signal or a cam-sensor circuit fault.
P0335 and P0340 are signal-family codes. P0016 is a relationship code. That difference matters because an engine with no valid crank signal may not even know where it is in the cycle, while an engine with P0016 may still see both signals but decide their timing relationship is no longer believable. If you treat all three like random sensor swaps, you miss the main diagnostic split.
P0335 often produces the cleanest no-RPM story. The engine may crank and never fire, may stall hot and restart after cooling, or may show zero or irrational RPM while cranking. Because the crank signal is fundamental, loss of that signal can shut down spark and injector timing quickly. That pattern is much more electrical or sensor-path driven than a subtle chain-stretch story.
P0340 can overlap with no-start, but many vehicles still crank longer than normal and eventually run because the ECU can fall back on crank information for part of the strategy. When that happens, long crank, unstable sync, or reduced power may show up without the total dead-feeling that often comes with a missing crank signal. If P0340 appears together with P0016 or P0011, stop pretending it has to be only a cam sensor.
P0016 does not merely say a sensor went quiet. It says the cam and crank events no longer line up the way they should. That can come from stretched timing components, slipped alignment, phaser problems, poor oil control, or a signal issue bad enough to fake correlation loss. Startup rattle, recent timing work, low oil history, and repeatable hard-start behavior all strengthen the mechanical-timing branch.
If there is no RPM while cranking, P0335 gets much stronger immediately. If RPM is present but cam sync never stabilizes, P0340 or timing-correlation trouble rises. If both signals exist yet the ECU still flags correlation, P0016 or P0017 deserves more respect than another quick connector spray. The point is to ask whether the signals are absent, unstable, or merely disagreeing with each other.
P0335 alone after a hot stall often leans crank sensor or wiring. P0340 with P0011 or P0016 leans toward timing-system involvement. P0016 with startup rattle, low-oil history, or recent chain work leans hardest toward mechanical timing drift. If P0016 and P0335 appear together, do not assume the cheapest sensor wins; a bad signal can confuse correlation logic, but a mechanically out-of-time engine can also make the signals look wrong.
First, verify battery voltage and cranking speed so low-voltage noise does not pollute the story. Second, watch RPM and sync status during cranking. Third, inspect the crank and cam sensor connectors and harness routing before buying anything. Fourth, if correlation codes, chain noise, or VVT faults are present, inspect oil condition and move toward mechanical timing verification instead of playing sensor roulette.
If the engine lacks RPM, think crank signal first. If the engine has RPM but weak or inconsistent sync, think cam signal and timing context together. If both signals are present but their relationship is implausible, think correlation and timing drift first. The winning diagnosis is the one that matches what the engine actually knows during cranking, not the part name people mention most online.