how do I fix the check engine light on my Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

• Gather tools and necessary parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Addressing Error Codes

• Sub-step 1: Connect the OBD-II scanner to the diagnostic port under the dashboard.
• Sub-step 2: Record any trouble codes displayed and look up their meanings.
• Sub-step 3: Clear the codes and take the vehicle for a test drive to see if the codes return.

3. Inspect and Replace Components

• Sub-step 1: If the gas cap is faulty (not sealing properly), replace it with a new one.
• Sub-step 2: If the air filter is dirty, remove the air filter housing, replace the filter with a new one, and reassemble.
• Sub-step 3: If spark plugs or ignition coils are worn, remove the old plugs/coils, install new ones, and torque to manufacturer specifications (usually around 13-15 ft-lbs for spark plugs).

4. Check for Vacuum Leaks

• Sub-step 1: Inspect all vacuum hoses for cracks or disconnections.
• Sub-step 2: Replace any damaged hoses and ensure all connections are secure.

5. Reconnect Battery

• Reconnect the negative battery terminal and ensure it is tight.