General Information

Component Location





General Description

The CVVT (Continuously Variable Valve Timing) system is installed to the chain sprocket of the intake camshaft. This system controls the intake camshaft to provide the optimal valve timing for every driving condition. The ECM controls the Oil Control Valve (OCV), based on the signals output from mass air flow, throttle position and engine coolant temperature. The CVVT controller regulates the intake camshaft angle using oil pressure through the OCV. As result, the relative position between the camshaft and the crankshaft becomes optimal and the engine torque improves, fuel economy improves, exhaust emissions decrease under overall driving conditions.

DTC Description

When the enable condition is satisfied The ECM checks that high and low outputs (Voltage level) are observed when OCVs are commanded. When a OCV output failure is detected, the appropriate fail counter is incremented.
If the failure threshold is exceeded 5 seconds during one diagnostic test (10 seconds), the test is failed and DTC is stored.
MIL (Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.

DTC Detecting Condition





Specification





Diagnostic Circuit Diagram





Signal Waveform & Data








Fig.1) Normal waveform of OCV at idle.
Fig.2) Normal waveform of OCV at acceleration. (3500 rpm)

The oil control valve is commanded by a pulse-with-modulated signal from the engine control unit. A duty cycle of zero commands the cam phaser to its default position. A duty cycle of 100% commands the cam phaser to its maximum phased position. When the phaser must be controlled to an intermediate position, the duty cycle is maintained in the region of the 'hold position'. This is a medium duty cycle, usually between 35% and 65%, depending on temperature and voltage conditions.