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

• •Check engine light illuminated
• •Reduced engine performance
• •Increased fuel consumption
• •Failed emissions test
• •Unusual exhaust odors

1. 1Scan for error codes using an OBD-II scanner to confirm the P0420 code and check for any other related codes.
2. 2Inspect the exhaust system visually for any obvious damage or leaks, particularly around the catalytic converter.
3. 3Check the operation of the upstream and downstream oxygen sensors with a multimeter to ensure they are functioning correctly.
4. 4Monitor the live data from the engine control unit (ECU) to evaluate the oxygen sensor readings and catalytic converter efficiency.
5. 5Inspect for any exhaust leaks upstream of the catalytic converter that could affect readings.
6. 6Verify the condition of the catalytic converter by performing a temperature test (measuring inlet and outlet temperatures).

After completing the repair, verify that the issue has been resolved:

• ✓Test the affected component to ensure it functions correctly
• ✓Check for any error codes or warning lights
• ✓Monitor the vehicle for a few days to ensure the issue does not recur

To prevent this issue from occurring again:

• •Follow the manufacturer's recommended maintenance schedule
• •Address warning signs early before they develop into major issues
• •Use quality parts and fluids recommended for your vehicle
• •Keep detailed records of all repairs and maintenance

• •OBD-II scanner
• •Socket set
• •Torque wrench
• •Multimeter
• •Wrench set

• •Upstream oxygen sensor
• •Downstream oxygen sensor
• •Catalytic converter