how to fix P0135 code in Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative terminal of the battery to ensure safety.
• Raise the vehicle securely if access to the underside is needed.

2. Remove the Oxygen Sensor

• Locate the upstream oxygen sensor (Bank 1) near the exhaust manifold.
• Use an oxygen sensor socket or wrench to carefully unscrew the sensor from the exhaust pipe.
• Disconnect the electrical connector from the oxygen sensor.

3. Inspect and Replace

• Inspect: Check the old oxygen sensor for signs of physical damage, contamination, or excessive wear.
• Replace: If the sensor is faulty, install the new oxygen sensor by threading it into the exhaust pipe and tightening it to the manufacturer’s specification (typically 30-50 ft-lbs).
• Reconnect: Plug the electrical connector back into the new oxygen sensor.

4. Check Wiring and Connectors

• Inspect the wiring harness leading to the oxygen sensor for any signs of fraying or damage.
• If any issues are found, repair or replace the wiring as necessary to ensure proper connection.

5. Reconnect Battery and Test

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature to ensure the oxygen sensor is functioning.