If you’re experiencing a “Lost Communication With Active Grille Air Shutter Module A” error on your Ford vehicle, you’re not alone. This issue commonly arises after installing an aftermarket intercooler, which often necessitates the removal of the factory active grille shutter (AGS) assembly. This article explains the problem, its potential consequences, and provides a simple solution.
Understanding the Active Grille Air Shutter System
Ford utilizes active grille shutters to optimize aerodynamics and engine temperature. These adjustable flaps, located in front of the radiator and intercooler, open and close to regulate airflow. While beneficial for fuel efficiency and warm-up times, the entire AGS assembly is often removed to accommodate larger aftermarket intercoolers, particularly common in performance modifications for vehicles like the Focus ST.
Consequences of AGS Removal
Removing the AGS assembly typically results in two primary issues:
Diagnostic Trouble Code (DTC)
A soft DTC, specifically related to lost communication with the AGS module, will be stored in the vehicle’s computer. While a soft code won’t trigger a check engine light (CEL), it can cause problems during state inspections. Some jurisdictions may fail a vehicle due to this code. While it can be temporarily suppressed with software like Forscan, this isn’t a permanent fix and raises concerns about future EPA regulations regarding tuning software capabilities.
Exposed Electrical Connector
With the AGS assembly removed, the electrical connector for the shutter motor is left exposed to the elements. This leaves it vulnerable to dirt, salt, moisture, and subsequent corrosion. This corrosion can affect the connector’s 12V power supply, ground, and the LIN (Local Interconnect Network) bus communication wire.
Potential for Further Damage
A shorted LIN bus, caused by corrosion in the exposed AGS connector, can interfere with other devices sharing the same network, such as the alternator. Many have needlessly replaced alternators, batteries, and cables due to charging system issues ultimately stemming from a corroded AGS connector.
Simple Solution: Reinstall the Shutter Motor
The most straightforward and effective solution is to reinstall the AGS shutter motor.
- Retrieve the Motor: Remove the shutter motor from the discarded AGS assembly.
- Reconnect: Plug the motor back into its electrical connector.
- Secure the Motor: Securely zip-tie the motor out of the way, preferably under the driver-side headlight, protecting it from the elements.
This simple procedure eliminates the DTC and prevents corrosion-related issues, requiring no special calibration. Unfortunately, the AGS assembly is typically sold as a unit, and aftermarket replacements for the entire assembly are not readily available for all Ford models. Used motors (part number BM51-8476-AB) can often be found online for various Ford models (2013-2018) ensuring compatibility with your specific vehicle is crucial.
Alternative Solution: Connector Removal
If the AGS function has been permanently disabled via tuning software, consider removing the connector entirely. This eliminates the risk of future corrosion-related problems. Ensure the connector is properly sealed to prevent moisture ingress; simply wrapping it with tape or a bag is not a reliable long-term solution.
Conclusion
The “lost communication with active grille air shutter module A” error is a common issue with a simple fix. By reinstalling the AGS shutter motor, you can avoid potential problems and ensure the long-term health of your vehicle’s electrical system. If the AGS is disabled, removing the connector altogether provides a permanent solution to prevent future corrosion and electrical issues.
