my BMW 3 Series G20/G21 (2019-2024) check engine light is on, what should I check first?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface and the engine is off.
• Disconnect the battery before working on electrical components to avoid shorts.

2. Scan and Record Error Codes

• Use an OBD-II scanner to retrieve and document any error codes.
• Clear the codes and take the vehicle for a test drive to see if the CEL returns.

3. Inspect and Replace Faulty Components

• Inspect Spark Plugs:

  • Remove the ignition coils using a socket set.
  • Pull out the spark plugs; inspect for wear, fouling, or damage.
  • Replace with OEM spark plugs if necessary, torque to manufacturer specifications (usually around 15-20 Nm).

• Check Fuel System:

  • Inspect fuel lines for leaks and ensure all connections are tight.
  • Replace the fuel filter if it shows signs of clogging or if it has reached its service interval.

• Examine Air Intake:

  • Remove the air intake duct and inspect for cracks or loose fittings.
  • Clean or replace the air filter if it is dirty.

4. Reconnect Battery and Test

• After repairs, reconnect the battery.
• Start the engine and monitor for any unusual sounds or behavior.
• Verify that the check engine light is no longer illuminated.