The active grille shutter system consists of a shutter assembly and an actuator motor. The assembly includes the housing, shutters, retainer, and a wiring harness. Active grille shutters are serviced as an assembly, the shutters are not serviceable individually. The actuator can be serviced individually.

Operation

This controlled vent system is primarily designed to maximize fuel economy by reducing drag on the vehicle. The grille shutters automatically close to block airflow through the cooling system when not needed. Closing the active grille shutters helps to improve aerodynamics Figure 2 - This is how the active grille shutter system looks fully closed.at high speeds. The shutters open to reduce underhood temperatures when needed. The grille shutter system is also used to control coolant temperatures, HVAC performance, and exhaust emissions depending on the vehicle speed.

The shutters are linked together, with one of the individual shutters attached to the actuator by the retainer. When the grille shutter actuator moves, it moves the attached shutter, which in turn, causes the other linked shutters to move.

The shutters are regulated by the powertrain control module (PCM), and can be set into 16 different positions, from fully closed (see Figure 2), to fully open (see Figure 3), depending on the amount of cooling air required. The grille shutter actuator receives the position commands from the PCM. The PCM determines the required positions based on inputs such as vehicle speed, coolant temperature, ambient air temperature, and air conditioning system pressure.

Figure 3 - This is how the active grille shutter system looks fully open.During normal operation, the grille shutters are fully open when the engine is off. When starting the engine from cold, the grille shutters will remain closed as long as possible to help reach the most efficient operating temperatures more quickly. This also helps reduce fuel consumption and emissions.

Damage Analysis

The grille shutter assembly is located at the front of the vehicle behind the boron-alloyed steel bumper reinforcement (see Figure 1 again). The bumper reinforcement has crushboxes that attach to the front lower rails. If the crushboxes collapse during a collision, the bumper reinforcement could be forced into the grille shutter assembly.

When analyzing damage, look for obstructions in the shutters that would prevent proper operation of the system. Since all of the shutters are linked together, all it would take is one obstruction to cause a bind. This could be a broken piece of a part or a foreign object. The grille shutter system has a dedicated fuse, and an obstruction may cause the fuse to blow. Also, check that the grille assembly is properly aligned in the opening.

Automatic Calibration

When the engine is started, an automatic calibration of the grille shutter system takes place. This calibration process cannot be initiated manually.

Calibration typically takes about 15-20 seconds. The process occurs until calibration is successful, or a fault is detected. Any failure of the system for over 10 seconds continuously will result in the actuator positioning the shutters fully open. There is no indication to the driver when a grille shutter system fault is present, however, a diagnostic trouble code is set in the PCM.

Conclusion

The 2012 Ford Focus may be equipped with the active grille shutter system. Located in the front of the vehicle, the system is in a vulnerable position during frontal collisions. Except for the actuator, no parts of the system can be serviced individually. When repairs are required, the active grille shutters, housing, retainer, and wiring harness must be replaced as an assembly.

This article first appeared in the June 29, 2011 edition of the I-CAR Advantage Online.

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