why does my Honda Civic 10th Generation (2016-2021) check engine light keep coming on

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to reset the engine control unit (ECU) after repairs.

2. Address Error Codes

• Use the OBD-II scanner to read and document all codes.
• Clear the codes and take the vehicle for a test drive to see if the CEL returns.
• If specific codes indicate issues (e.g., P0420 for catalytic converter efficiency), proceed with targeted repairs.

3. Replace Faulty Components

• If spark plugs are worn, remove the ignition coils and replace the spark plugs using a socket set (typically 10-14 ft-lbs torque).
• If air filter is dirty, remove the air intake cover and replace the air filter with a new one, ensuring a proper seal.
• If the gas cap is faulty, replace it with a new OEM gas cap.

4. Inspect and Repair Emission Components

• Check the exhaust system for leaks or rust, particularly around the catalytic converter and O2 sensors.
• If codes indicate issues with the O2 sensors, replace them using a wrench (typically 30-40 ft-lbs torque) while ensuring the connector is secure.

5. Reset the ECU

• After all repairs, reconnect the battery.
• Use the OBD-II scanner to clear any error codes.
• Check that the CEL does not reappear after a short test drive.