why does my BMW 3 Series G20/G21 (2019-2024) check engine light keep coming on?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, screwdriver set.
• Allow the engine to cool down before starting any work.
• Disconnect the battery to ensure safety while working on electrical components.

2. Address Error Codes

• Sub-steps:
  1. Use the OBD-II scanner to reset the error codes after repairs.
  2. If the codes indicate a specific issue (e.g., P0420 for catalytic converter efficiency), proceed to fix that specific component.
  3. Replace any faulty sensors or components as identified by the error codes (e.g., oxygen sensors, MAF sensor).

3. Inspect and Replace Components

• Sub-steps:
  1. If the gas cap is damaged, replace it with a new one.
  2. Replace the air filter if it is dirty or clogged.
  3. If any leaks are found in the exhaust system, repair or replace the affected sections (e.g., gaskets, pipes).

4. Final Checks

• Sub-steps:
  1. Reconnect the battery.
  2. Start the engine and check for any leaks or unusual noises.
  3. Test drive the vehicle to ensure the check engine light does not return.