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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface and set to "Park" mode.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter
• Remove the upstream (pre-catalytic converter) oxygen sensor:
  1. Locate the oxygen sensor on the exhaust manifold.
  2. Using the O2 sensor socket, carefully unscrew the sensor.
  3. Inspect the sensor for damage or contamination.
• If faulty, replace with a new oxygen sensor.
• Reinstall the sensor and ensure it is securely tightened (typically 30 Nm).

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust sealant
• Inspect the catalytic converter:
  1. Check for physical damage or excessive carbon buildup.
  2. If damaged, remove the catalytic converter by unbolting it from the exhaust system.
• Install the new catalytic converter:
  1. Position the new converter in place.
  2. Bolt it securely, applying the manufacturer's specified torque (typically 40-50 Nm).
  3. Use exhaust sealant on the joints to prevent leaks.

4. Reset the Engine Control Module (ECM)

• With the new components installed:
  1. Reconnect the battery.
  2. Use an OBD-II scanner to clear the P0420 code from the ECM.
  3. Start the engine and allow it to reach operating temperature.