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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery (negative terminal) to prevent electrical issues.

2. Address Error Codes

• Sub-step 1: Review the error codes retrieved from the OBD-II scanner and note any specific codes related to the issue.
• Sub-step 2: Research each code to understand potential underlying problems (e.g., P0171 for lean condition).

3. Check and Replace Faulty Components

• Sub-step 1: If the fuel cap is faulty, replace it with an OEM equivalent.
• Sub-step 2: For faulty sensors, remove and replace using proper torque specifications (usually around 10-15 Nm for sensor mounting).
• Sub-step 3: If spark plugs are worn, remove them using a socket set and replace them with the manufacturer-recommended type. Torque to specifications (typically around 25-30 Nm).

4. Repair or Replace Other Affected Parts

• Sub-step 1: For damaged air intake components, remove the defective part and replace it (e.g., air filter or hose).
• Sub-step 2: Inspect and repair any exhaust leaks around the catalytic converter; replace gaskets as needed.

5. Reconnect Battery

• Reconnect the battery terminal and ensure connections are tight.

6. Reset Check Engine Light

• Use the OBD-II scanner to clear error codes and turn off the check engine light.