Active Grille Air Shutter - If Equipped

WARNING: This page is about a different variant/trim than selected.

During normal driving operation, the Powertrain Control Module (PCM) determines vane position from the thermal condition of the vehicle. This information is an output of the electric cooling fan control logic.

The vane position depends on the following:

The engine coolant temperature
The Air Conditioning (A/C) demand
The ambient air temperature
The fuel temperature
The Terrain Response® mode selection.

If vehicle speed reaches 180 km/h (112 mph) the vanes move to the fully open position. The vanes resume a calculated opening position when vehicle speed decreases to 140 km/h (87 mph).

In the case of electric cooling fan after-run, the vanes remain open. When the fan after-run ends, the vanes close and the motor will send a signal to the PCM indicating it is ready to power down.

Calibration Mode

When the Powertrain Control Module (PCM) shuts down, the motor loses its memory. Therefore a calibration is required every time the ignition is switched on unless the PCM has remained active between ignition off and ignition on. For example in case of electric cooling fan after-run.

Calibration only commences after the engine has started.

The calibration process opens and closes the vanes to find the end stops and range of motion between them. This range of movement is checked and if it is within the specified limits, the cycle is passed. This cycle can take up to 16 seconds.

The software allows for a total of six calibration attempts.

If the first attempt fails, as soon as a position demand exceeds 45%, it will complete the remaining five attempts. One after the other, until they either pass a calibration or fail all six attempts.

If the vanes pass the third calibration, the remaining attempts are saved for the rest of the drive cycle. For example when the vanes had been frozen for the first two attempts and have since thawed out.

A 'Calibration Failed Fault' DTC will only be stored if the calibration fails from the first attempt and all attempts are used up.

The vanes will then be commanded to open as much as possible.

If the first calibration passes, then a 'Calibration Failed Fault' Diagnostic Trouble Code (DTC) cannot be set until the next drive.

NOTE: The motor is very sensitive to voltage drops from engine cranking and may trigger a further calibration.

Jet Wash Mode

Jet wash mode allows the motor to fully open the vanes and then power down so that the radiator can be cleaned.

To activate jet wash mode:

Start the engine.
Stop the engine and turn the ignition off.
Turn the ignition on (do not start the engine).
Select Terrain Response® sand mode.
Turn the ignition off.

This sequence prevents to enter jet wash mode accidentally when the ignition is turned off in sand mode.

The vanes will default to fully open if the calibration has been completed or not. (See calibration mode article above)

When the position feedback shows that the vanes are fully open, the motor will indicate to the Powertrain Control Module (PCM) that it is ready to power down.

Fault Diagnosis

If there is a fault with the active grille air shutter, the 'Engine Over Temperature' warning is displayed in the Instrument Cluster (IC) message center. For each fault, a flag is set and after a calibrated de-bounce time, a Diagnostic Trouble Code (DTC) is stored in the PCM.

The following faults can be detected:

Mechanical blockage fault - Motor encounters too much resistance and stalls. Max Torque = 0.7 - 0.8 Nm. When blocked, the motor will try to re-calibrate up to maximum number of attempts as described in the calibration article.
Calibration failed fault - Fault stored if all calibration attempts have failed in that drive cycle.
Electrical fault - Motor reports an internal electrical fault.
Supply voltage fault - Motor supply voltage falls outside the range 7.5V - 17.5V.
Thermal shutdown fault - Motor circuits exceed their inbuilt temperature threshold.
Disconnect fault - Linkage between the motor and the vanes becomes disconnected.
Local Interconnect Network (LIN) Bus communication fault and Node detection fault - A fault with the motor, its signal wire or its supply that causes a breakdown in signals to the Powertrain Control Module (PCM). If the motor is still operational and only the signal wire has a short circuit/open circuit, then the motor will fail safe fully open after 10 seconds of not receiving a signal.