how to replace a faulty ignition coil in my BMW 3 Series E90/E91 (2005-2012)?

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, socket set, torque wrench, multimeter, replacement ignition coils, and any necessary gaskets.
• Ensure the vehicle is parked on a level surface, and the engine is cool.

2. Disconnect Battery

• Disconnect the negative terminal of the battery to prevent any electrical shorts.
• Use a socket to loosen the terminal clamp and remove the cable.

3. Remove Engine Cover

• Use a socket wrench to remove the bolts securing the engine cover.
• Carefully lift off the cover and set it aside to access the ignition coils.

4. Remove Old Ignition Coils

• Identify the faulty ignition coil based on diagnostic results.
• Disconnect the electrical connector from the ignition coil by pressing the tab and pulling it away.
• Use a socket to remove the bolt securing the ignition coil to the engine.
• Pull the ignition coil straight out from the spark plug well.

5. Install New Ignition Coils

• Apply a small amount of dielectric grease to the rubber boot of the new ignition coil.
• Insert the new ignition coil into the spark plug well, ensuring it is seated properly.
• Secure it in place with the bolt and tighten it to the manufacturer’s specified torque (typically around 8 Nm).
• Reconnect the electrical connector to the ignition coil, ensuring it clicks into place.

6. Reassemble Components

• Replace the engine cover and secure it with the bolts.
• Reconnect the negative terminal of the battery.