P0016: OBD-II code P0016 means the crankshaft and bank 1 camshaft position sensors are out of sync — usually a stretched timing chain, VVT phaser issue, or bad sensor.

Symptoms

• The check engine light is on, often accompanied by a rattle from the timing cover at cold start.
• Rough idle, hesitation, and reduced power because ignition and injection timing are off.
• The engine may crank longer before starting, and in severe cases stall or fail to start at all.

Common causes

• A stretched or jumped timing chain — very common on high-mileage VVT engines, especially GDI designs.
• A stuck VVT oil control solenoid or worn cam phaser holding the cam out of its base position.
• A failed crankshaft or camshaft position sensor with drift or missing pulses causing correlation errors.

What to do?

Watch cam and crank timing in live data while cranking — a phase error of more than a few degrees confirms mechanical misalignment. Change engine oil, then command the VVT solenoid on/off with a scan tool. If VVT tests good, inspect timing chain stretch — replace the chain, tensioner, and guides as a set on affected engines. Replace sensors last.