how to fix P0420 code on my Toyota Tacoma N300 (2016-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the battery to avoid electrical issues during repairs.

2. Inspect Exhaust System

• Tools Required: Socket set, flashlight
• Sub-steps:
  1. Lift the vehicle using a jack and secure it with jack stands.
  2. Visually inspect the entire exhaust system from the manifold to the tailpipe for any signs of damage or leaks.
  3. Repair or replace any damaged components as necessary.

3. Test Oxygen Sensors

• Tools Required: Multimeter
• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Set the multimeter to measure voltage and connect it to the signal wire of the upstream sensor.
  4. Start the engine and observe the voltage; it should fluctuate between 0.1V to 0.9V.
  5. Repeat the procedure for the downstream sensor; it should show a less fluctuating reading (typically around 0.5V).

4. Replace the Catalytic Converter (if necessary)

• Tools Required: Wrench set, oxygen sensor socket, gasket scraper
• Sub-steps:
  1. If the catalytic converter is determined to be faulty, unbolt the exhaust pipes connected to it.
  2. Remove the old catalytic converter, taking care to remove any old gaskets or debris.
  3. Install the new catalytic converter, ensuring it is properly aligned and secured with the bolts to the exhaust pipes.
  4. Replace any gaskets as needed.

5. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the battery terminals.
  2. Use an OBD-II scanner to clear the P0420 code from the system.
  3. Start the engine and allow it to idle for a few minutes.