Use Japan parts 

• BMW E90 (3 Series, 5th generation, facelift version, called ''LCI'' – Life Cycle Impulse)
• Model Years: Approx. 2008–2012 (for E90 LCI)
• Engine: N46 2.0L inline-4 petrol engine

Engine Overview:

• Engine code: N46B20 (specifically, it could be N46B20U1 or N46B20O1, depending on market)
• 2.0 liters, naturally aspirated, DOHC, Valvetronic (variable valve lift) and VANOS (variable valve timing).
• Improved reliability and emissions compliance over earlier N46 versions.

ECU (Engine Control Unit):

• Manufacturer: Siemens/VDO (a division of Continental)
• Model: Siemens MSV70 or sometimes MSD80 (depends on exact version and region)
• Functionality:
  
• Controls fuel injection, ignition timing, throttle (drive-by-wire), variable valve timing (VANOS), and Valvetronic systems.
• Monitors emissions (O2 sensors, EGR, etc.) and complies with Euro 4 or early Euro 5 standards.
• Handles communication with other modules over BMW’s CAN Bus system.
• Incorporates features like immobilizer (EWS/CAS) security.
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Features the ECU manages:

• Fuel injection (sequential, electronic multipoint)
• Ignition control (coil-on-plug ignition)
• Throttle actuation (electronic throttle control)
• Idle control (via Valvetronic adjustment)
• VANOS (adjusts intake and exhaust camshafts for efficiency and power)
• Valvetronic (adjusts valve lift without throttle plate)
• On-Board Diagnostics (OBD-II / EOBD for EU models)
• Cooling system management (fan speeds, electric water pump logic where applicable)
• Emissions systems (monitoring catalytic converters, EGR, secondary air injection where fitted)

Physical Location:

• The ECU is mounted in the E-box (electrical box) near the right (passenger side) firewall under the hood, protected from heat and moisture.

Communication:

• OBD-II port for diagnostics (K-Line and CAN communication protocols)
• Works closely with CAS module (Car Access System) for starting authorization (anti-theft).