Cam phasers are part of the variable valve timing (VVT) system in newer vehicles. They are sprockets that adjust the position of the camshaft in relation to the crankshaft and are tuned with a computer-controlled servo. The VVT system is designed to provide power when needed or to provide fuel economy when you don’t need the power, increasing fuel economy and engine efficiency. The cam phasers adjust the position of the camshaft by advancing or retarding the timing in the engine based on whether you need power or fuel economy. The VVT system uses oil pressure supplied by the VVT solenoid to activate the cam phaser, and the powertrain control module (PCM) uses inputs from various engine sensors to tell the VVT solenoid to advance or retard the timing.
Symptoms of a bad cam phaser or VVT system include the engine light coming on, giving a cam sensor or actuator code, telling you the camshaft is not in the expected position. The engine may sound more like a race engine, idle more roughly, and become less fuel-efficient. Throttle response will suffer, and in the later stages, the vehicle may start sounding like a race car but driving poorly.
Replacing cam phasers is an involved process, and it is not recommended that the average weekend mechanic undertake a cam phaser replacement themselves. If you plan to add or replace a cam phaser to your vehicle’s engine, follow the manufacturers recommendation very closely, take your time, and make sure you have all the required tools before you start.
