how to resolve P0135 oxygen sensor issue on Volkswagen Golf MK7.5 (2020-Present)?

Solution

1. Preparation

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

2. Inspect and Repair Wiring

• Sub-steps:
  • Visual inspection of the wiring harness leading to the oxygen sensor.
  • Look for frayed wires, corrosion, or loose connections.
  • If damage is found, repair or replace the affected wiring.
• Tools Required: Wire strippers, electrical tape, soldering iron (if needed)

3. Replace Oxygen Sensor

• Sub-steps:
  • Locate the upstream oxygen sensor (usually near the catalytic converter).
  • Use an oxygen sensor socket to unscrew the old sensor from the exhaust.
  • Apply anti-seize compound to the threads of the new sensor.
  • Install the new oxygen sensor and torque it to manufacturer specifications (typically around 30 Nm).
• Tools Required: Oxygen sensor socket, torque wrench, anti-seize compound

4. Check and Replace Fuse (if necessary)

• Sub-steps:
  • Locate the fuse box and identify the fuse associated with the oxygen sensor circuit.
  • Remove the fuse and check for continuity using a multimeter.
  • Replace the fuse with a new one of the same rating if it is blown.
• Tools Required: Fuse puller or pliers, multimeter

5. Reconnect Battery and Clear Codes

• Sub-steps:
  • Reconnect the negative battery terminal.
  • Use the OBD-II scanner to clear the P0135 code from the ECU.
  • Start the engine and allow it to reach operating temperature.