how to troubleshoot check engine light codes in Toyota Highlander Third Generation (2014-2019)?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, multimeter, torque wrench, basic hand tools.
• Safety Warnings: Disconnect the battery before working on electrical systems. Allow the engine to cool before opening the hood.

2. Addressing Specific Codes

• Refer to the code definitions:
  • If the code is related to the oxygen sensor, proceed to replace the faulty sensor.
  • If the code indicates a misfire (e.g., P0300), check spark plugs and ignition coils for wear.
  • For catalytic converter issues (e.g., P0420), inspect and test the converter for blockages or damage.

3. Replace or Repair Faulty Components

• Remove defective components:
  • For oxygen sensors: Disconnect the wiring harness, remove the sensor using a socket, and install the new sensor.
  • For spark plugs: Remove ignition coils, pull out old spark plugs, and install new ones with specified torque (typically 13-15 lb-ft).

4. Clear Error Codes

• Use the OBD-II scanner to clear the error codes after repairs.
• Reconnect the battery if it was disconnected for safety.

5. Test Drive

• Take the vehicle for a test drive to ensure that the Check Engine Light does not re-illuminate and that symptoms are resolved.