how to fix P0420 code on Tesla Model 3 Original (2017-2023)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to prevent electrical shorts.
• Ensure the vehicle is on a level surface and secured with wheel chocks.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the connectors from the upstream and downstream oxygen sensors.
• Using the O2 sensor socket, unscrew the sensors from the exhaust system.
• Install the new oxygen sensors by screwing them in and tightening them to the manufacturer's specifications (typically 30-40 Nm).
• Reconnect the sensor wiring harness.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool
• Remove any heat shields that obstruct access to the catalytic converter.
• Use the socket set to unbolt the catalytic converter from the exhaust system.
• Inspect the old catalytic converter for signs of blockage or damage.
• Install the new catalytic converter, ensuring it is aligned correctly.
• Torque the bolts to the manufacturer's specifications (usually around 25-30 Nm).
• Reinstall any heat shields removed earlier.

4. Clear Codes and Test Drive

• Reconnect the vehicle's battery.
• Use an OBD-II scanner to clear the P0420 code from the system.
• Perform a test drive under various conditions to ensure the code does not return.