Porsche Cayenne E3 (2018-Present) engine light on with code P0420, how to fix?

Solution

1. Preparation

• Gather all necessary tools and parts for the repair.
• Disconnect the battery to ensure safety during the repair process.
• Allow the engine to cool down before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, multimeter
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Disconnect the electrical connectors from both oxygen sensors.
  3. Use the O2 sensor socket to remove the sensors from their mounting points.
  4. Install the new oxygen sensors and torque them to the manufacturer’s specification (typically around 30 Nm).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket
• Sub-steps:
  1. Remove any heat shields if obstructing access to the catalytic converter.
  2. Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
  3. Inspect the catalytic converter for signs of damage or clogging.
  4. Install the new catalytic converter using a new exhaust gasket.
  5. Torque the bolts to the manufacturer's specifications.

4. Reset the Check Engine Light

• Tools Required: OBD-II scanner
• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
  3. Disconnect the scanner after the code has been cleared.