Possible causes

– Dirty Oil
– Faulty Valve Timing Control (VTC)
– Low engine oil level
– Valve Timing Control (VTC) harness is open or shorted circuit.
– Valve Timing Control (VTC) circuit poor electrical connector
– Damaged ECM

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Possible Lack/Loss of power
– Possible Engine rough idle

P0012 HYUNDAI Description

The Engine Control Module (ECM) optimizes the valve timing using the Valve Timing Control (VTC). The ECM sends a target dutyandcycle control signal to the VTC. This control signal regulates the oil pressure supplied to the VTC. The VTC can advance or retard the engine timing.