how to fix P0420 code on Tesla Model 3 Highland (2024-present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, basic socket set, jack and jack stands, smoke machine.
• Gather necessary replacement parts, if needed.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Inspect and Replace Oxygen Sensors

1. Disconnect the battery to ensure safety while working on electrical components.
2. Locate the upstream and downstream oxygen sensors (usually near the exhaust manifold and catalytic converter).
3. Remove the oxygen sensors using a socket or wrench.
   • Note: Be cautious of corrosion; penetrating oil may help.
4. Install the new oxygen sensors in the reverse order, ensuring proper torque as per manufacturer specifications (typically 30-40 ft-lbs).
5. Reconnect the battery.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Lift the vehicle using a jack and secure with jack stands.
2. Remove the exhaust components connected to the catalytic converter using a socket and ratchet.
3. Inspect the catalytic converter for physical damage or blockage.
4. Remove the old catalytic converter by unbolting it from the exhaust system.
5. Install the new catalytic converter, ensuring to follow torque specifications (usually 25-30 ft-lbs).
6. Reassemble the exhaust components, ensuring all connections are tight.

4. Clear Codes and Test

1. Use the OBD-II scanner to clear the P0420 code.
2. Start the vehicle and allow it to reach operating temperature.
3. Perform a test drive to ensure that the check engine light does not reappear.