how to fix P0303 code in BMW X3 F25 (2011-2018)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to prevent electrical shock.
• Ensure the engine is cool for safe handling.

2. Replace Spark Plug

• Remove the engine cover if necessary.
• Use a socket set to carefully remove the spark plug from cylinder 3.
• Inspect the spark plug for carbon buildup or damage.
• Install a new spark plug (OEM recommended) and torque to manufacturer's specifications (typically around 15 lb-ft).

3. Test/Replace Ignition Coil

• Disconnect the ignition coil connector for cylinder 3.
• Remove the ignition coil using a socket set.
• Test the ignition coil with a multimeter (specifications typically around 0.5-0.6 ohms for primary resistance).
• If the coil fails the test, replace it with a new one and ensure it is seated properly.

4. Inspect/Replace Fuel Injector

• Disconnect the fuel injector connector for cylinder 3.
• Remove the fuel rail if necessary to access the injector.
• Use a fuel pressure gauge to check for adequate fuel pressure.
• If the injector is faulty, replace it with a new one, ensuring proper alignment and sealing.

5. Reassemble and Test

• Reconnect all components and connectors.
• Reconnect the negative battery terminal.
• Start the engine and allow it to idle; monitor for any check engine lights or misfires.