why does my Toyota Highlander XU70 (2020-Present) check engine light keep coming back

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Address Error Codes

• Sub-step 1: Refer to the OBD-II scanner results to identify specific error codes.
• Sub-step 2: Research and understand the meaning of each code to determine necessary repairs.

3. Inspect and Replace Spark Plugs and Ignition Coils

• Sub-step 1: Remove the engine cover (if applicable) using a socket set.
• Sub-step 2: Unscrew and remove the ignition coils using a ratchet and socket.
• Sub-step 3: Remove the spark plugs using a spark plug socket and ratchet; inspect for wear or fouling.
• Sub-step 4: Replace spark plugs with OEM equivalents, ensuring they are gapped correctly.
• Sub-step 5: Reinstall ignition coils and secure them with the appropriate torque setting (usually around 7-10 ft-lbs).

4. Check for Vacuum Leaks

• Sub-step 1: Use a smoke machine to detect leaks or visually inspect hoses and gaskets.
• Sub-step 2: Replace any damaged hoses or gaskets.

5. Test and Replace the Gas Cap

• Sub-step 1: Check the gas cap for cracks or damage.
• Sub-step 2: If necessary, replace with an OEM gas cap ensuring it clicks securely when closed.

6. Clear Error Codes

• Sub-step 1: Reconnect the negative battery terminal.
• Sub-step 2: Use the OBD-II scanner to clear error codes and reset the check engine light.