Removing the front kidney grille shutters on a BMW, while retaining the motor, can trigger error codes related to the Active Cooling Air Flap Control (AKKS) system. This article addresses common issues and solutions when encountering these errors, specifically focusing on the CD9203 error code related to upper and lower stop limits, often experienced after coding out the AKKS module.
The AKKS system controls the airflow through the radiator for optimal engine temperature and aerodynamic efficiency. When the shutters are removed, the system’s sensors cannot detect the upper and lower stop limits, resulting in error codes. While coding out the AKKS seems like a straightforward solution, complexities arise depending on the vehicle’s build date.
Before July 2020 (pre-S18A), coding out the AKKS within the DME (Digital Motor Electronics) involved modifying the “AKKS” parameter. Setting this parameter to 0x01 indicated shutters only on top, 0x00 signified no flaps, 0x02 represented top and bottom flaps, and 0x03 remained unused. However, for vehicles manufactured after July 2020 (S18A onwards), the system shifted to separate parameters: “LKS_OBEN” (Air Flap Control_Top) and “LKS_UNTEN” (Air Flap Control_Bottom). Each parameter could be individually enabled (0x01) or disabled (0x00).
Even after correctly coding out the AKKS or the individual LKS parameters, error codes might persist, especially the lower stop limit error. This can happen even if only the upper flaps were originally affected. One potential solution is to completely disconnect the power connectors to the motors for both upper and lower flaps. This eliminates any possibility of residual signals being sent back to the ECU (Engine Control Unit), potentially triggering the errors.
Another critical factor to consider is the specific values read by the system. If the AKKS reads 00, and both LKS_OBEN and LKS_UNTEN also read 00, the system should theoretically recognize the absence of the shutters and not trigger errors. However, inconsistencies in the coding process or underlying software issues could still lead to problems.
If you’ve encountered persistent error codes after removing the kidney grille shutters and coding out the AKKS, double-check the coding process specific to your vehicle’s build date. Ensure the correct parameters (AKKS, LKS_OBEN, LKS_UNTEN) are set to 00 or 0x01 as appropriate. If issues persist, disconnecting the motor power connectors might resolve the problem. If errors continue after these steps, consult a BMW specialist or refer to technical documentation for advanced troubleshooting. A comprehensive diagnostic scan can pinpoint any underlying issues beyond the AKKS system that might be contributing to the error codes. Remember, accurate diagnosis is crucial for effective repairs.
