how to fix P0420 code in Volvo XC90 Second Generation (2015-2024)

Solution

1. Preparation

• Ensure the vehicle is parked on a flat surface and the engine is off.
• Gather necessary tools and parts.
• Disconnect the negative battery terminal.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor:
  1. Locate the upstream O2 sensor (before the catalytic converter).
  2. Use the O2 sensor socket to unscrew the sensor.
  3. Install the new sensor and torque to manufacturer specifications (typically around 30 lb-ft).
• Repeat for the downstream oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if needed).
• Remove the catalytic converter:
  1. Raise the vehicle and secure it on jack stands.
  2. Disconnect the exhaust pipes from the catalytic converter (may require cutting if rusted).
  3. Unbolt the catalytic converter from the mounting brackets.
  4. Remove it from the vehicle.
• Install the new catalytic converter:
  1. Position the new catalytic converter and bolt it into place.
  2. Reconnect the exhaust pipes, ensuring a tight fit.
  3. Make sure to replace any gaskets if needed.

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code.