why does my Toyota Corolla E210 (2019-2024) have a check engine light and runs rough?

Solution

1. Preparation

• Gather tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cooled down.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Scan and Interpret Error Codes

• Connect the OBD-II scanner to the diagnostic port.
• Turn on the ignition without starting the engine.
• Retrieve and note all error codes.
• Research codes to identify potential issues (e.g., P0300 for random misfires).

3. Inspect and Replace Spark Plugs

• Remove the engine cover if necessary.
• Use a socket set to remove the spark plug wires or ignition coils.
• Extract spark plugs using a spark plug socket.
• Inspect plugs for wear; replace with OEM-spec plugs if damaged or fouled.
• Reinstall new plugs, ensuring proper torque (typically 13-15 lb-ft).

4. Check and Clean the Fuel System

• Use a fuel pressure gauge to check the fuel pressure against specifications.
• If pressure is low, check the fuel filter and pump for blockages or failures.
• If necessary, clean the fuel injectors using a fuel injector cleaning kit.
• Reconnect any lines and ensure there are no leaks.

5. Inspect Air Intake and Vacuum Lines

• Check the air intake duct for cracks or loose connections.
• Inspect the Mass Air Flow (MAF) sensor for dirt; clean it with MAF cleaner.
• Examine all vacuum lines for leaks; replace any damaged hoses.

6. Reconnect Battery and Test

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.
• Monitor for any reoccurrence of the check engine light.