how to fix P0421 code in Tesla Model S Original (2012-2020)

Learn how to diagnose and fix P0421 exhaust system issue in Tesla Model S (2012-2020). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle's battery to prevent any electrical issues.
• Required tools: OBD-II scanner, multimeter, socket set, torque wrench, exhaust leak detector.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Remove the oxygen sensor connectors.
  3. Use a socket wrench to unscrew the oxygen sensors from their mounting locations.
  4. Install new oxygen sensors, ensuring they are tightened to manufacturer specifications (usually around 30 lb-ft).
  5. Reconnect the sensor connectors.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Disconnect any exhaust hangers or clamps securing the catalytic converter.
  2. Remove the catalytic converter from the exhaust system using a socket wrench.
  3. Inspect the new catalytic converter for any damage before installation.
  4. Install the new catalytic converter, ensuring it is properly aligned and secured with bolts (typically tightened to 20 lb-ft).
  5. Reattach all exhaust hangers or clamps.

4. Check for Exhaust Leaks

• Sub-steps:
  1. Start the vehicle and visually inspect for any exhaust leaks.
  2. Use an exhaust leak detector if necessary to confirm there are no leaks in the system.
  3. Repair any leaks found by replacing gaskets or tightening loose connections.