how to fix P0420 code on my Tesla Model 3 Highland (2024-present)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the vehicle’s 12V battery to prevent electrical shocks.
• Allow the vehicle to cool down if it has been running.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, wrench set
• Remove the upstream and downstream oxygen sensors using the O2 sensor socket.
• Inspect the sensors for damage or contamination.
• If faulty, replace with new OEM sensors, ensuring they are properly torqued to manufacturer specifications.
• Reconnect the O2 sensors to their respective connectors.

3. Inspect and Replace Catalytic Converter

• Tools Required: Jack and jack stands, socket set, exhaust pipe cutter (if necessary), gasket scraper, high-temperature gasket maker, torque wrench
• Raise the vehicle securely using a jack and jack stands.
• Remove any protective covers to access the catalytic converter.
• Disconnect the exhaust pipes from the catalytic converter by removing the bolts using a socket set.
• If necessary, cut the exhaust pipe to remove the catalytic converter.
• Clean the mating surfaces with a gasket scraper to ensure a proper seal.
• Install the new catalytic converter, applying high-temperature gasket maker if required, and torque the bolts to the specified torque settings.

4. Reconnect Battery and Clear Codes

• Reconnect the 12V battery.
• Use the OBD-II scanner to clear the P0420 code and any associated codes.