Monitor Description

The ECM optimizes the intake valve timing using the VVT (Variable Valve Timing) system to control the intake camshaft. The VVT system includes the ECM, the camshaft timing oil control valve and the VVT controller (camshaft timing gear assembly). The ECM sends a target duty-cycle control signal to the camshaft timing oil control valve assembly. This control signal regulates the oil pressure supplied to the VVT controller. The VVT controller can advance or retard the intake camshaft.

If the difference between the target and actual intake valve timing is large, and changes in the actual intake valve timing are small, the ECM interprets this as a VVT controller stuck malfunction and sets a DTC.

• Example:
• A DTC is stored when the following conditions 1 and 2 are met:
  • 1. It takes 5 seconds or more to change the valve timing by 5°CA.
  • 2. After condition 1 is met, the camshaft timing oil control valve is forcibly activated for 10 seconds.
• DTC P0011 (Advanced Cam Timing) is subject to 1 trip detection logic.
• DTC P0012 (Retarded Cam Timing) is subject to 2 trip detection logic.
• These DTCs indicate that the VVT controller cannot operate properly due to camshaft timing oil control valve assembly malfunctions or the presence of foreign objects in the camshaft timing oil control valve assembly.