how to fix P0420 code on Tesla Model S Plaid/Refresh (2021-present)

Learn how to diagnose and fix P0420 exhaust system issues in Tesla Model S Plaid. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety while working with electrical components.
• Allow the vehicle to cool down before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use an O2 sensor socket or wrench to remove the sensors from their positions.
  4. Install new oxygen sensors, ensuring they are torqued to manufacturer specifications (generally around 30-40 lb-ft).
  5. Reconnect the electrical connectors securely.

3. Examine and Replace the Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove any heat shields or mounting brackets securing the catalytic converter.
  2. Unbolt the catalytic converter from the exhaust system (may require penetrating oil if rusted).
  3. Inspect the old catalytic converter for signs of physical damage or blockage.
  4. Install the new catalytic converter, ensuring proper alignment and tightness of bolts (typically 30-40 lb-ft).
  5. Reattach any heat shields or brackets removed during disassembly.

4. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the vehicle’s battery terminals.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle’s memory.
  3. Start the engine and allow it to idle for a few minutes.

Tools Required:

• OBD-II scanner
• O2 sensor socket or wrench
• Socket set
• Torque wrench
• Temperature probe

Parts Required:

• Upstream oxygen sensor
• Downstream oxygen sensor
• Catalytic converter (if found faulty)

Estimated Repair Time: 2-4 hours

Safety Warnings:

• Disconnect the battery before working on electrical systems.
• Ensure the engine is cool before working on the exhaust system to avoid burns.