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

Solution

1. Preparation

• Gather tools and parts before starting the repair.
• Tools Required: OBD-II scanner, socket set, torque wrench, oxygen sensor socket, safety gloves, and goggles.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Inspect and Replace Oxygen Sensors

1. Disconnect Battery:

   • Disconnect the negative terminal of the battery to avoid electrical issues.

2. Remove Oxygen Sensors:

   • Use an oxygen sensor socket to carefully unscrew the upstream and downstream oxygen sensors from the exhaust system.

3. Inspect Sensors:

   • Check the sensors for signs of damage or contamination. If they are faulty, replace them with new ones.

4. Install New Sensors:

   • Apply anti-seize compound on the threads of the new oxygen sensors.
   • Install the new sensors and torque them to the manufacturer's specifications (typically around 30 Nm or 22 lb-ft).

3. Inspect and Replace Catalytic Converter (if necessary)

1. Check for Damage:

   • Inspect the catalytic converter for cracks, dents, or rust. If damaged, proceed with replacement.

2. Remove the Exhaust Manifold:

   • Loosen and remove bolts securing the exhaust manifold to access the catalytic converter.

3. Unbolt Catalytic Converter:

   • Unscrew the bolts connecting the catalytic converter to the exhaust system. Use a penetrating oil if bolts are rusty.

4. Install New Catalytic Converter:

   • Position the new catalytic converter and secure it with bolts, tightening to manufacturer’s torque specifications (typically around 40 Nm or 30 lb-ft).

5. Reassemble Exhaust:

   • Reattach the exhaust manifold and ensure all bolts are properly tightened.

4. Clear Codes and Test Drive

1. Reconnect Battery:

   • Reconnect the negative battery terminal.

2. Clear Codes:

   • Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.

3. Test Drive:

   • Take the vehicle for a test drive to monitor for any reoccurrence of the code or symptoms.