Principles Of Operation

Active Grille Shutter System

Principles of Operation

When the engine is turned off, the grille shutter actuator moves the grille shutters to the full open position. When the engine is started, a calibration of the grille shutter system occurs, which typically takes 15-20 seconds. The grille shutter system performs the calibration sequence by moving the actuator and shutters through their full 90 degree sweep to detect the end positions (open/close). The calibration sequence can begin in either direction, open or closed, and continues until it is successful or a fault is detected. It is possible for a long pause to occur between the 2 portions (open/close) of the calibration sequence. Calibration of the grille shutter system cannot be manually requested, it only occurs as determined by the grille shutter actuator. If certain faults are present (such as shutter blocked or actuator error) a recalibration is initiated in an attempt to resolve the concern. If the concern is not resolved after 3-4 attempts, a DTC is set in the PCM. Other faults also trigger a recalibration request, but not until a grille shutter DTC is set in the PCM.

The Local Interconnect Network (LIN) supports bi-directional communication between the grille shutter actuator and PCM, allowing the grille shutter actuator to communicate position and fault information to the PCM. The PCM reports grille shutter system DTCs after the fault information is communicated by the grille shutter actuator for a predetermined amount of time. Any failures of the LIN (Local Interconnect Network) for over 10 seconds continuously, results in the grille shutter actuator moving the grille shutters to the full open position. There is no indication to the driver that a fault with the grille shutter system is present or that a grille shutter system DTC is set in the PCM.