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 Powertrain Control Module (PCM).

The following faults can be detected:

• Mechanical blockage fault - Motor encounters too much resistance and stalls. The maximum Torque is 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 is 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 7.5 V - 17.5 V.
• Thermal shutdown fault - Motor circuits exceed their in-built 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 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.