A type of variable valve timing system that dynamically adjusts the opening and closing of intake valves. It uses engine oil pressure directed through hydraulic actuators to phase the camshaft relative to the timing gear. This allows the engine to optimize airflow across the RPM range, improving low-end torque while maintaining high-end horsepower and reducing emissions.
The scanner shows a code for the sequential valve timing actuator, so check the oil pressure before throwing a new solenoid at it.
Dirty or low engine oil is the leading cause of failure for these systems, as the tiny hydraulic passages easily clog with sludge.
Related terms
Variable valve timing
An engine technology that alters when intake and exhaust valves open and close.
Continuous variable valve timing
An engine valvetrain system that constantly adjusts camshaft phasing to match operating conditions.
ECU
The primary computer that manages engine performance, fuel delivery and emissions.