BMW E90 E91 335i 306HP Engine N54 ECU Kit DME 7575875 + CAS3 + Key Automatic

BMW E90 E91 335i 306HP Engine N54 ECU Kit DME + CAS3 + Key Automatic is a complete engine control kit designed for BMW 3 Series models with the N54 engine and automatic transmission. The kit includes the DME engine control unit, the CAS3 module, and a matched key, which facilitates the restoration of proper powertrain electronics operation after a failure or during an engine swap. This solution allows for consistent matching of immobilizer and control components, reducing diagnostic and programming time.

Specifications and technical data

• SKU: 7575875-1
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7575875
• Substitutable numbers: 12147616431 5WK93628 61356943834 12147575875, 7616431 6943834 7575875
• Gearbox type: Automatic
• Category: Control Modules

Purpose and function of the ECU kit

The presented engine control unit kit is dedicated to the BMW 3 Series E90/E91 in the 335i version with the 306 HP N54 engine and automatic transmission. The combination of the DME, CAS3 module, and key ensures a coherent start authorization system, which is crucial when replacing electronics in vehicles with advanced security systems. This helps avoid many problems related to component incompatibility and communication errors in the vehicle's bus.

Kit construction and benefits of a complete configuration

The ECU kit includes three main elements: the engine control unit responsible for managing the N54 engine, the CAS3 module handling immobilizer functions, and a key matched to this module. Such a configuration allows for maintaining the integrity of the security system and facilitates adaptation in a vehicle where the original controller or the entire system has been damaged. The completeness of the kit translates into fewer programming steps and faster restoration of full powertrain functionality.

In the case of the N54 engine, which uses extensive control strategies for turbocharging, injection, and ignition, the use of the appropriate DME is essential for engine stability and proper cooperation with the automatic transmission. An ECU kit matched to a specific powertrain configuration helps reduce the risk of adaptation errors and incorrect drivetrain responses.

Integration with automatic transmission

The N54 engine in the 335i version works with an automatic transmission that requires precise data exchange with the engine control unit. A properly selected DME + CAS3 + key kit supports correct communication between the engine and the transmission, which affects gear shift smoothness, throttle response, and stability in both comfort and dynamic modes. A properly integrated engine control unit is key to maintaining factory powertrain performance parameters and the correct operation of safety functions.

Application in diagnostics, repair, and upgrades

The ECU kit can be used both for standard repairs after electronic failure and for more advanced projects, such as engine swaps or powertrain conversions within the same generation of the BMW 3 Series. Thanks to the presence of the CAS3 module and the key, it is possible to limit coding to the absolute minimum, which is particularly important in workshops specializing in BMW electronics. A consistent set of controllers also facilitates verifying system operation on a diagnostic bench before installation in the vehicle.

If you want to better understand when choosing a used engine control unit is justified and how to safely select such an element for your car, it is worth reading the guide: The second life of electronics – when is it worth opting for used engine controllers, comfort modules, and parking sensors?. The article discusses practical aspects of selecting and verifying used automotive electronics.

Expanding the control system in BMW – Computers and controllers

If you are planning a comprehensive repair or upgrade of the engine area in your BMW and need other elements from the same group, such as additional control modules, auxiliary controllers, or onboard system controllers, check out the available parts in the BMW computers and controllers category.