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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical issues during repair.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream and downstream oxygen sensors from the exhaust system.
• Inspect the sensors for damage or contamination; replace if necessary.
• Install new sensors by threading them into place and tightening to manufacturer specifications (usually 30-40 lb-ft).

3. Repair or Replace Catalytic Converter

• Tools Required: Socket set, jack, jack stands, exhaust hanger removal tool
• If the catalytic converter is damaged, remove the exhaust hangers using the exhaust hanger removal tool.
• Unbolt the catalytic converter from the exhaust system and remove it.
• Install the new catalytic converter by aligning it with the exhaust system and securing it with bolts, torquing them to specifications (usually 30-40 lb-ft).
• Reinstall exhaust hangers to support the catalytic converter.

4. Clear Codes and Test Drive

• Reconnect the negative battery terminal.
• Use an OBD-II scanner to clear the P0420 code from the system.
• Perform a test drive to monitor vehicle performance and check for reoccurrence of the code.