Monitor Description

The ECM optimizes the exhaust valve timing using the Variable Valve Timing (VVT) system to control the exhaust camshaft. The VVT system includes the ECM, cam timing oil control solenoid assembly, camshaft timing oil control valve assembly (exhaust camshaft timing gear bolt assembly) and camshaft timing exhaust gear assembly. The ECM sends a target duty-cycle control signal to the cam timing oil control solenoid assembly. The camshaft timing oil control valve assembly (exhaust camshaft timing gear bolt assembly) is operated to control the oil pressure supplied to the camshaft timing exhaust gear assembly based on this signal. The camshaft timing gear assembly can advance or retard the exhaust camshaft.

If the difference between the target and actual exhaust valve timing is large, and changes in the actual exhaust valve timing are small, the ECM interprets this as the camshaft timing exhaust gear assembly stuck malfunction and stores a DTC.

1. Example:
2. A DTC is stored when the following conditions are met:
   1. It takes 5 seconds or more to change the valve timing by 5°CA.
   2. After the above condition is met, the cam timing oil control solenoid assembly is forcibly activated for 9.5 seconds.

These DTCs indicate that the camshaft timing exhaust gear assembly cannot operate properly due to a camshaft timing oil control valve assembly (exhaust camshaft timing gear bolt assembly) malfunction or the presence of foreign matter in the camshaft timing oil control valve assembly (exhaust camshaft timing gear bolt assembly).