how to troubleshoot P0302 code in BMW 5 Series G30/G31 (2017-2024)

Solution

1. Preparation

• Tools Required: OBD-II scanner, compression gauge, fuel pressure gauge, socket set, torque wrench.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Inspect and Replace Ignition Components

• Sub-steps:
  1. Remove the engine cover (if applicable).
  2. Disconnect the electrical connectors from the ignition coil for cylinder 2.
  3. Remove the ignition coil using the appropriate socket.
  4. Inspect the spark plug for wear or damage; replace if necessary.
  5. Install a new ignition coil if the old one is faulty.
  6. Reconnect the electrical connector and ensure it is secure.

3. Inspect and Clean Fuel Injector

• Sub-steps:
  1. Locate the fuel injector for cylinder 2.
  2. Disconnect the fuel line (use a rag to catch any fuel spills).
  3. Remove the fuel injector using the proper socket.
  4. Inspect the injector for clogs or debris; clean or replace as necessary.
  5. Reinstall the fuel injector ensuring it is seated properly.
  6. Reconnect the fuel line and check for leaks.

4. Perform Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 2.
  2. Install the compression gauge into the spark plug hole.
  3. Crank the engine for a few seconds and note the compression reading.
  4. Compare the reading to the manufacturer's specifications.
  5. If the compression is low, further investigation may be needed for mechanical issues.

5. Check Fuel Pressure

• Sub-steps:
  1. Locate the fuel rail and attach the fuel pressure gauge.
  2. Turn the ignition to the "ON" position (do not start the engine) to check for fuel pressure.
  3. Compare the reading to the recommended specifications.
  4. If pressure is low, inspect the fuel pump and fuel filter.