Engine
What do the crankshaft and camshaft sensors do and what happens when they fail?
The crankshaft sensor tells the control unit how fast the engine is turning and where it is, and the camshaft sensor which cylinder is in which stroke. Without the crankshaft signal most engines will not start or will stall while driving; a camshaft sensor fault usually makes cranking longer. Typical codes are P0335, P0340 and P0016.
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Why are they so important?
With the crankshaft signal the control unit decides when to inject and, on gasoline engines, when to fire the spark. It also uses it to detect misfires.
With the camshaft signal it knows which stroke each cylinder is in and controls variable valve timing, if there is any.
What does P0016 mean?
That the crankshaft and camshaft positions do not line up as they should. It can be a sensor, but also a stretched or jumped timing chain or belt, or a variable valve timing problem.
Do not ignore it: a worn timing system can end in serious engine damage.
What causes the faults?
Sensors failed from heat, dirty or oily connectors, chafed wires, a damaged reluctor wheel or oil problems (level or quality) on engines with variable valve timing.
General guidance only: every manufacturer and model has its own details. Always follow your vehicle's manual and, if in doubt, ask a workshop.
Related
Related trouble codes
- P0335Crankshaft position sensor A, circuit: malfunction
- P0340Camshaft position sensor A (bank 1 or single sensor), circuit: malfunction
- P0016Correlation fault between crankshaft position and camshaft position (bank 1, sensor A)
- P0011A camshaft position: timing over-advanced or system performance (bank 1)
- P0010A camshaft position actuator A (bank 1), control circuit open
Related symptoms
- Engine cranks but will not start: causes and what to do
- Car stalls by itself: causes and what to do
- Car slow to start: causes and what to do
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Frequently asked questions
Can I drive with a faulty crankshaft sensor?
It is risky: the engine can stall while driving. If it stalls or will not start, call for assistance.
Does the oil level affect these codes?
On engines with variable valve timing, yes: oil moves the phasers.
Does replacing the sensor always fix it?
No: if the cause is the timing system or the wiring, the code comes back.