BMW 3 E90 ELECTRICAL WIRING DIAGRAMS

Electrical diagrams and recommendations for the maintenance of your car.

The device of BMW 3 serie cars (E90, E91 body models 318d, 320d, 320i, 325i, 330i) since 2004, equipped with gasoline engines N46 B18, N46 B20, N52 B25, N52 B30 with a volume of 1.6, 1.8, 2.0, 3.0 liters and diesel engines M47TU2, M47TU2OL with a volume of 2.0 liters.

Separate sections of the publication provide recommendations for maintenance and electrical circuits (electrical circuits) of the car. Also, the materials of the publication will help you choose the necessary parts for BMW 3.

Electrical System General – E90 06-11

Wipers and Washers – E90 06-11

Switches – E90 06-11

Instruments – E90 06-11

Lights – E90 06-11

Heating and Air-conditioning – E90 06-11

Radio – E90 06-11

Electrical Component Locations – E90 06-11

Electrical Wiring Diagrams – E90 06-11

OBD On-Board Diagnostics – E90 06-11

Bmw E90 Owners Manual without iDrive

🔋 1. Battery and charging system

Fast battery discharge — often due to “current leakage” in idle mode (parasitic consumption).

Wear of the generator (especially the voltage regulator) — leads to unstable power supply to the electronics.

A faulty IBS sensor on the battery terminal can give false power supply errors.

💡 2. Lighting

Burning out of headlights and brake lights due to overheating of the connectors.

Oxidation of contacts in the rear lights → blinking or complete absence of light.

Problems with adaptive headlights (AFS) — error in the control unit or servo drives.

📡 3. Electronic units and data buses

Failures of the FRM module (Footwell Module) — headlights, window lifters, turn signals stop working.

CAS module failures (access and start system) — the car does not respond to the key or displays an immobilizer error.

CAN bus problems due to oxidation of connectors in the passenger compartment or engine compartment.

🪟 4. Window lifters and electric drives

Wear of the window lift mechanism or cables → the glass gets stuck.

Malfunctions of motors and control buttons.

Broken wires in the door corrugation (often the driver's door) due to repeated openings.

🌧 5. Moisture and corrosion of connectors

Water getting into the JBE or FRM units due to clogged drains.

Oxidation of contacts under the hood and under the seats → random errors in sensors and modules.

🎛 6. Sensors and auxiliary systems

False errors on the coolant level sensor - due to oxidized contacts.

Malfunction of parking sensors (PDC) - from moisture or mechanical damage.

Malfunctions in the climate control (IHKA unit) due to poor contacts.