MONITOR DESCRIPTION
The ECM optimizes the valve timing by using the Variable Valve Timing (VVT) system to control the intake camshaft. The VVT system includes
the ECM, the camshaft timing oil control valve assembly and the VVT controller.
The ECM sends a target duty-cycle control signal to the camshaft timing oil control valve assembly. This control signal regulates the oil pressure
applied to the VVT controller. The VVT controller can advance or retard the intake camshaft. The ECM calibrates the intake valve timing by setting
the intake camshaft to the most retarded angle while the engine is idling. The ECM closes the camshaft timing oil control valve assembly to retard
the cam. The ECM stores this value as the VVT learning value. When the difference between the target and actual intake valve timing is 5锟斤拷CA
(crankshaft angle) or less, the ECM stores it.
If the VVT learning value matches the following conditions, the ECM determines the existence of a malfunction in the VVT system, and sets the
DTC.
- The VVT learning value: Less than 18.5锟斤拷CA, or more than 43.5锟斤拷CA.
- The above condition continues for 18 seconds or more.
This DTC indicates that the intake camshaft has been installed toward the crankshaft at an incorrect angle, caused by factors such as the timing chain
having jumped a tooth.
This monitor begins to run after the engine has idled for 5 minutes.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
No comments:
Post a Comment