The Ford U0284:00-6c diagnostic trouble code (DTC) often appears after installing an aftermarket intercooler on a Focus ST, requiring removal of the active grille shutter (AGS) assembly. This article explains why this code appears, potential issues, and solutions for effectively managing the U0284:00-6C code.
Why Does U0284:00-6C Occur?
Ford designed the AGS system with adjustable flaps in front of the radiator and intercooler to improve aerodynamics and engine warm-up. Upgrading to a larger aftermarket intercooler often necessitates removing the entire AGS assembly, resulting in the U0284:00-6C DTC. This code indicates a lost communication with the AGS module. While it’s a “soft” code and won’t illuminate the check engine light (CEL), it can cause issues with state inspections in certain jurisdictions.
Potential Problems Associated with U0284:00-6C
Beyond inspection hassles, the dangling AGS connector poses a more significant risk. Exposed to the elements under the bumper cover, this connector is vulnerable to dirt, salt, and moisture, leading to corrosion. This corrosion can affect the connector’s 12V power supply, ground, and Local Interconnect Network (LIN) bus communication wire. A shorted LIN bus can disrupt other systems sharing the bus, such as the alternator, potentially causing charging system issues and unnecessary replacement of components like alternators, batteries, and cables.
Solutions for the U0284:00-6C Code
The simplest solution involves reconnecting the AGS shutter motor. Locate the motor within the removed assembly and plug it back into the connector. Securely zip-tie the motor out of the way under the driver-side headlight. This eliminates the DTC and requires no calibration.
While purchasing a new AGS assembly might seem logical, Ford only sells the entire unit. Unfortunately, aftermarket replacements like those available for other manufacturers (e.g., Dorman for Subaru) are not currently available for the Ford Focus ST.
A used AGS motor (part number BM51-8476-AB) compatible with the 2013-2018 Focus ST can be found online for around $35-$100 USD. This motor is used across various Ford models, so ensure compatibility within the specified year range.
Addressing the Disabled AGS System
If the AGS system has been disabled through tuning software, it’s highly recommended to completely remove the AGS connector to prevent future corrosion issues. Simply taping or bagging the connector provides insufficient long-term protection.
Conclusion
The U0284:00-6C code, resulting from aftermarket intercooler installation, can be effectively managed by reconnecting the AGS motor or removing the connector entirely if the AGS system is disabled. This prevents potential electrical problems and ensures the vehicle remains problem-free. Addressing this seemingly minor issue can save significant time and money in the long run.
