why does my Tesla Model S Original (2012-2020) keep throwing a P0420 error code

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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, infrared thermometer, socket set.
• Allow the vehicle to cool down completely before starting any work to prevent burns.

2. Oxygen Sensor Inspection

• Disconnect the battery to prevent electrical shock.
• Locate the upstream and downstream oxygen sensors.
• Use a multimeter to check the voltage output:
  • For the upstream sensor, the voltage should fluctuate between 0.1V and 0.9V.
  • For the downstream sensor, it should be relatively stable, around 0.5V.
• If any sensor is out of specification, replace it.

3. Catalytic Converter Inspection

• If the oxygen sensors are functioning correctly, proceed to inspect the catalytic converter.
• Remove the heat shields if necessary to access the catalytic converter.
• Check for any physical damage or signs of clogging.
• If a physical blockage is found, the catalytic converter will need to be replaced.

4. Exhaust System Check

• Inspect the entire exhaust system for leaks or damage that could affect the catalytic converter's performance.
• Tighten or replace any damaged components as necessary.
• Ensure there are no exhaust leaks upstream of the catalytic converter.

5. Reassembly and Testing

• Reinstall any components that were removed during inspection.
• Reconnect the battery.
• Clear the error codes using the OBD-II scanner.
• Start the vehicle and monitor for any reoccurrence of the P0420 code.