why does my Toyota Corolla E170 (2013-2019) check engine light come on randomly

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative terminal of the battery to prevent electrical shorts.

2. Addressing Diagnostic Trouble Codes

• Sub-step 1: Connect the OBD-II scanner to the vehicle's diagnostic port and retrieve the codes.
• Sub-step 2: Research the codes to identify specific issues (e.g., P0300 for random misfire).
• Sub-step 3: Based on the codes, proceed to check related components as identified in the diagnostic steps.

3. Inspect and Replace Components

• Sub-step 1: If codes indicate a misfire, remove the spark plugs and inspect for wear. Replace if necessary.
• Sub-step 2: If ignition coils are faulty, disconnect the wiring harness and remove the bolts securing the coils. Replace with new coils.
• Sub-step 3: For air filter issues, remove the air intake duct and replace the air filter with a new one.
• Sub-step 4: If the gas cap is faulty, replace it with a new OEM or equivalent part.

4. Reconnect Battery and Clear Codes

• Sub-step 1: Reconnect the negative terminal of the battery.
• Sub-step 2: Use the OBD-II scanner to clear the DTCs from the engine control module (ECM).

5. Final Checks

• Sub-step 1: Start the engine and monitor for any warning lights.
• Sub-step 2: Take the vehicle for a short test drive to ensure the issue has been resolved.