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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is on a level surface and safely raise the vehicle using jack stands.
• Disconnect the battery to prevent electrical hazards.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream (pre-catalytic) oxygen sensor:
  1. Locate the sensor on the exhaust manifold.
  2. Use an O2 sensor socket to unscrew the sensor.
  3. Install the new sensor and torque to manufacturer's specification (typically around 30 ft-lbs).
• Remove the downstream (post-catalytic) oxygen sensor:
  1. Locate the sensor after the catalytic converter.
  2. Unscrew the sensor using the O2 sensor socket.
  3. Install the new sensor and torque to specification.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if necessary)
• Remove the catalytic converter:
  1. Unbolt the exhaust flanges (both upstream and downstream) connecting the catalytic converter.
  2. If necessary, cut the exhaust pipe for easier removal.
  3. Remove the old catalytic converter from the vehicle.
• Install the new catalytic converter:
  1. Position the new catalytic converter in place.
  2. Bolt it to the exhaust flanges and torque to specification (typically around 30-35 ft-lbs).
  3. Reconnect any exhaust hangers and ensure everything is secure.

4. Clear Error Codes

• Reconnect the battery.
• Use an OBD-II scanner to clear the P0420 code.
• Start the engine and let it idle to ensure there are no leaks.