how to fix P0420 code on my Porsche Cayenne E3 (2018-Present)

Solution

1. Preparation

• Gather the necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream (pre-catalytic) oxygen sensor.
  • Use the O2 sensor socket to unscrew the sensor.
  • Inspect the sensor for damage; replace if necessary.
• Install the new upstream oxygen sensor and torque to manufacturer specifications (typically around 30 Nm).
• Repeat the process for the downstream (post-catalytic) oxygen sensor.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if needed).
• Raise the vehicle securely using a jack and jack stands.
• Locate the catalytic converter and inspect for physical damage or clogging.
• If replacement is necessary, disconnect the exhaust pipes from the catalytic converter using the socket set.
• Remove any mounting bolts securing the converter to the exhaust system.
• Install the new catalytic converter, ensuring it is properly aligned.
• Torque all bolts to manufacturer specifications (typically around 40 Nm).

4. Reset the Check Engine Light

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the error code from the vehicle's computer.