how do I fix the P0420 code on my Tesla Model 3 Original (2017-2023)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's 12V battery for safety.
• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, jack and jack stands.

2. Inspect and Replace Oxygen Sensors

• Inspect the sensors: Remove the upstream and downstream oxygen sensors using a socket wrench. Check for any signs of damage or contamination.
• Test functionality: Use a multimeter to test the output voltage of each sensor. If they are not within specification (typically 0.1V to 0.9V for upstream), replace them.
• Install new sensors: Apply anti-seize compound to the threads of the new sensors. Install the upstream sensor first, followed by the downstream sensor, tightening them to the manufacturer's specifications.

3. Inspect and Replace Catalytic Converter

• Remove the catalytic converter: Support the vehicle on jack stands. Disconnect the exhaust pipes from both ends of the catalytic converter using a socket set. If bolts are rusted, use penetrating oil.
• Inspect for clogs: Check the inside of the catalytic converter for any signs of blockage or damage. If clogged, proceed with replacement.
• Install new catalytic converter: Position the new catalytic converter in place, aligning it with the exhaust system. Tighten all bolts to the manufacturer’s torque specifications.

4. Clear Codes and Test Drive

• Reconnect the battery: Once all components are replaced, reconnect the battery.
• Clear the OBD-II codes: Use the OBD-II scanner to clear the P0420 code and any related codes.
• Test drive the vehicle: Drive the car for at least 20-30 minutes to allow the vehicle to complete its readiness monitors.