what to do if my Tesla Model 3 Highland (2024-present) has a P0420 code

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative terminal of the battery to ensure safety.

2. Inspect and Test Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors connected to the exhaust system.
  2. Use a multimeter to check the voltage output of the upstream O2 sensor; it should fluctuate between 0.1V and 0.9V.
  3. If the reading is outside this range, replace the faulty oxygen sensor.
• Tools Required: Multimeter, O2 sensor socket

3. Examine the Catalytic Converter

• Sub-steps:
  1. Inspect the catalytic converter for dents, rust, or signs of overheating.
  2. If damaged, remove the catalytic converter by loosening the bolts and disconnecting any clamps.
  3. Install a new catalytic converter, ensuring all connections are secure and torqued to manufacturer specifications.
• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if necessary)

4. Clear the P0420 Code

• Sub-steps:
  1. Reconnect the battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
• Tools Required: OBD-II scanner