what does it mean when my BMW 3 Series E90/E91 (2005-2012) has a P0302 code?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to ensure safety while working on the engine.
• Allow the engine to cool before beginning work.

2. Inspect and Replace Ignition Components

1. Remove the engine cover (if applicable) to access the ignition coil.
   • Tools Required: Socket set, ratchet
2. Disconnect the electrical connector from the ignition coil for cylinder 2.
3. Remove the ignition coil from cylinder 2 by unscrewing the bolt.
4. Inspect the ignition coil for any visible damage. Replace if necessary.
   • Parts Required: New ignition coil (if defective)
5. Replace the spark plug in cylinder 2.
   • Remove the spark plug using a socket wrench.
   • Check the gap on the new spark plug and install it to the manufacturer’s specification (usually around 0.028 inches for BMW).
   • Parts Required: New spark plug

3. Test and Replace Fuel Injector (if needed)

1. Locate the fuel injector for cylinder 2.
2. Disconnect the electrical connector and fuel line (use a fuel line removal tool if necessary).
3. Remove the fuel injector.
4. Test the injector using a multimeter to ensure it is within the manufacturer’s specifications.
5. Replace the fuel injector if it is found to be defective.
   • Parts Required: New fuel injector (if defective)

4. Perform Compression Test

1. Remove the spark plug from cylinder 2.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine and record the compression reading.
   • Compare the reading to the manufacturer's specifications.
   • If compression is low, further investigation into the engine's internal components may be required.