A camshaft position sensor is an electronic device used in modern gas and diesel engines, to monitor the relationship between the pistons and valves in the engine. This information is used by engine management systems to control the fuel injection or the ignition system timing and other engine parameters.

The camshaft position sensor’s role is particularly important in engines with variable valve timing. This method is also used to “synchronize” a four stroke engine upon starting, allowing the management system to know when to inject the fuel.