how to fix P0303 code in BMW X3 G01 (2018-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down before starting work.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench
• Remove the ignition coil from cylinder 3.
• Extract the spark plug using a spark plug socket.
• Inspect the spark plug for wear, carbon buildup, or damage.
• Replace the spark plug with a new one if necessary, ensuring it is gapped correctly (typically 0.028-0.032 inches).
• Reinstall the ignition coil securely.

3. Check and Replace Ignition Coil

• Tools Required: Socket set
• If the spark plug is in good condition, test the ignition coil for cylinder 3.
• If faulty, remove the ignition coil and replace it with a new one.
• Reassemble the components ensuring all connections are tight.

4. Inspect Fuel Injector

• Tools Required: Fuel injector puller (if necessary), multimeter
• Disconnect the electrical connector from the fuel injector for cylinder 3.
• Perform a resistance test on the injector; it should fall within the manufacturer's specifications (typically 12-16 ohms).
• If the injector is faulty, replace it with a new one.
• Reconnect the injector and ensure proper seating.

5. Check for Vacuum Leaks

• Inspect all vacuum hoses and gaskets around the intake manifold for leaks.
• Use a smoke machine or carburetor cleaner to detect leaks while the engine is running.
• Replace any damaged hoses or gaskets as needed.