why does my Toyota Highlander Fourth Generation (2020-present) 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.

2. Address Error Codes

• Use the OBD-II scanner to read error codes.
• Research codes to determine the specific fault, such as P0420 for catalytic converter efficiency.

3. Inspect and Replace Components

a. Gas Cap

• Step 1: Remove the gas cap and inspect for cracks or wear.
• Step 2: Clean the sealing surface on the filler neck.
• Step 3: Replace with a new gas cap if damaged.

b. Spark Plugs and Ignition Coils

• Step 1: Remove engine cover (if applicable) using a socket set.
• Step 2: Disconnect the ignition coil connectors.
• Step 3: Remove spark plugs using a spark plug socket.
• Step 4: Inspect plugs for wear; replace with OEM parts if necessary.
• Step 5: Reinstall ignition coils and connectors.

c. Air Intake System

• Step 1: Check air filter for dirt and debris; replace if necessary.
• Step 2: Inspect air intake hoses for cracks; replace as needed.

4. Clear Codes and Test Drive

• Step 1: Clear the error codes using the OBD-II scanner.
• Step 2: Start the engine and monitor for any warning lights.
• Step 3: Conduct a test drive to ensure the issue is resolved.