how to fix P0135 oxygen sensor error on Volkswagen Golf Eighth Generation (2020-present)?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to prevent any electrical short circuits.
• Raise the vehicle using a jack and secure it on jack stands if needed for access.

2. Remove the Old Oxygen Sensor

• Locate the upstream oxygen sensor (typically near the exhaust manifold).
• Use an oxygen sensor socket or a wrench to carefully unscrew the sensor from the exhaust system.
• Disconnect the wiring harness from the sensor.

3. Inspect and Clean

• Inspect the oxygen sensor port for carbon build-up or debris.
• Clean the threads of the port with a wire brush to ensure a proper seal for the new sensor.

4. Install the New Oxygen Sensor

• Apply anti-seize compound to the threads of the new oxygen sensor (if not pre-coated).
• Screw the new oxygen sensor into the exhaust port by hand to prevent cross-threading.
• Tighten the sensor to the manufacturer's specified torque (typically around 30-40 Nm, but refer to the specific service manual).
• Reconnect the wiring harness to the new sensor.

5. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0135 code from the vehicle’s computer.

6. Test Drive the Vehicle

• Perform a test drive under various conditions to ensure the check engine light does not reappear and that engine performance is restored.