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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Inspect the upstream and downstream oxygen sensors for signs of damage or contamination.
• If faulty, remove the old sensor:
  1. Use the O2 sensor socket to unscrew the sensor.
  2. Clean the threads of the sensor port.
• Install the new sensor:
  1. Apply anti-seize compound to the threads of the new sensor.
  2. Torque the new sensor to the manufacturer's specifications (usually around 30-40 ft-lbs).

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack stands, exhaust pipe cutter or saw, gaskets
• Inspect the catalytic converter for physical damage or blockage.
• If replacement is needed:
  1. Raise the vehicle and secure it on jack stands.
  2. Remove the exhaust hangers using a socket set.
  3. Cut the exhaust pipes on either side of the catalytic converter if necessary.
  4. Install the new catalytic converter, ensuring proper alignment.
  5. Reinstall hangers and secure all connections.

4. Clear Codes and Test Drive

• Reconnect the battery.
• Use an OBD-II scanner to clear the P0420 code.
• Test drive the vehicle to monitor for any reoccurrence of the code.