As you know, when conventional, front-engine, liquid-cooled, internal combustion vehicles are being driven, air is drawn through the grille and into the engine compartment. This air is either sucked in by the radiator fan or forced in by the movement of the car as it is driven. The majority of that air then passes through the fins of the radiator located directly behind the grille. This helps cool down the coolant within the radiator, which in turn keeps the engine cool.

Unless a vehicle’s engine is working extremely hard or the car is in a hot climate, there is often more air entering the engine compartment than is needed to keep the engine cool. All that air entering the engine compartment adds a significant amount of aerodynamic drag to the car, increasing the amount of energy needed to move it along, which decreases gas mileage. Higher speeds result in higher aerodynamic drag.

Active Grille Shutter System

The active grille shutter is located at the front bumper lower opening, and according to the signal from the ECM, the actuator operates to perform an open/close movement of the flap to control the amount of airflow taken into the engine compartment. One of the easiest ways to save fuel is to make a car smoother and slipperier above 40 MPH, because that is when the energy required to overcome wind resistance starts to rise. It is at those higher speeds when the Active Grille Shutter System vents on the Versa^® NOTE™ automatically adjust. The Active Grille Shutter System operates to control airflow through the radiator. It opens at lower speeds to help keep the engine cool and closes at higher speeds to help reduce drag, which improves the vehicle’s fuel efficiency. While driving, the Active Grille Shutter System automatically adjusts the shutter opening to reduce aerodynamic drag. This cuts turbulence (that air has to escape from the engine compartment somewhere), so the airflow is then routed around the car’s nose and over the rest of the body.

The reduction in airflow reduces drag and helps the Versa^® NOTE™ slip through the air more easily. This, in turn, reduces the amount of energy needed to push the car along, helping increase gas mileage.

If the engine gets too hot, the active shutter system can automatically reopen the grille, ensuring much-needed air can reach the radiator to prevent the engine from overheating.

System Operation

The ECM controls the active grille shutter actuator based on the detected vehicle status through respective modules and sensors for vehicle speed, coolant temperature, ambient air temperature and air conditioning system pressure.

Active Grille Shutter Operating Conditions

The active grille shutter is fully open when the vehicle stops or the ignition switch is turned OFF. The ECM operates the shutter to the closed position in order to perform shutter initial position learning when the ignition switch is turned ON. At the end of the initial position learning, the ECM operates the shutter to the open position until the vehicle speed reaches approximately 14 MPH. (The initial position learning is performed every time the ignition switch is turned OFF → ON.) While driving, after the initial position learning ends, the ECM operates the active grille shutter to the closed position when the vehicle reaches a specified speed for the first time. The ECM operates the shutter to the closed position when all the conditions of the active grille shutter are met: vehicle speed (approximately 19-88 MPH), engine coolant temperature (approximately less than 203°F), engine oil temperature (approximately less than 284°F), CVT fluid temperature (approximately 275°F), cooling fan ON and refrigerant pressure at 1.18 MPa or more. If the vehicle is driven at a high speed, the ECM operates the shutter to the open position when the vehicle reaches the specified speed of approximately 88 MPH in order to prevent the shutter from closing due to wind resistance. When the vehicle speed is reduced below the specified speed of 88 MPH, the ECM calibrates the active grille shutter to the closed position and then to the open position when the vehicle speed is less than 14 MPH.

The active grille shutter normally stops within zone “A.” Normal opening range is defined by zone “B” (90° ± 20°).

The active grille shutter actuator is equipped with a self-diagnosis function. When the active grille shutter actuator detects a malfunction, it transmits a diagnosis signal to the ECM, and the ECM records the active grille shutter malfunction.

DTC DETECTION LOGIC

A DTC is recorded if the active grille shutter stops and is stuck within zone “A” and a stuck error is detected or if the active grille shutter stops at a position beyond zone “A” and an overrun error is detected. A DTC is also recorded if the active grille shutter circuit is open or shorted.

If the ECM receives a 1st trip DTC P059F active grille shutter:

• Check to see if any foreign object is obstructing the active grille shutter (trash, leaves, snow, etc.).
• Check the continuity between the active grille shutter harness connector and the ground.
• Check the continuity between the active grille shutter harness connector and the active grille shutter relay harness connector.
• Check the continuity between the ECM harness connector and the active grille shutter harness connector.
• Check the voltage between the active grille shutter harness connector and the ground.

Repair or replace any error-detected parts as needed.

To verify operation, perform a calibration to command the shutter system to fully open and fully close with CONSULT.

1. Start the engine.

2. Select “ACTIVE GRILLE SHUTTER” in the “ACTIVE TEST” mode of “ENGINE” using CONSULT.

3. Touch “CALIBRTN.”

4. After the calibration completes, check the operation of the active grille shutter as follows.

Condition Active Grille Shutter

Select “CLOSE” when the shutter is Fully Opened.

Select “OPEN” when the shutter is Fully Closed.