what does the P0135 code mean for my Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

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

2. Access Oxygen Sensor

• Raise the vehicle using a jack and secure it with jack stands.
• Locate Bank 1 Sensor 1 (usually upstream of the catalytic converter on the exhaust manifold).

3. Remove Oxygen Sensor

• Disconnect the electrical connector from the oxygen sensor.
• Use an oxygen sensor socket to unscrew the sensor from its mounting location.
• Inspect the old sensor for signs of damage or excessive wear.

4. Install New Oxygen Sensor

• Apply anti-seize compound to the threads of the new oxygen sensor (if not pre-coated).
• Screw the new sensor into place and tighten it to the manufacturer's specified torque (typically around 30 lb-ft).
• Reconnect the electrical connector securely.

5. Reconnect Battery and Test

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature to ensure proper sensor operation.