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

Solution

1. Preparation

• Gather tools and materials.
• Disconnect the battery to prevent electrical shorts.
• Allow the exhaust system to cool before working on it.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream (pre-catalytic converter) oxygen sensor.
  • Use the O2 sensor socket to carefully unscrew the sensor from the exhaust manifold.
  • Inspect the sensor for damage or contamination.
• If damaged, install a new oxygen sensor and torque it to the manufacturer’s specifications (usually around 30 lb-ft).
• Repeat the process for the downstream (post-catalytic converter) oxygen sensor if needed.

3. Examine and Replace the Catalytic Converter

• Tools Required: Socket set, cutting tool (if necessary), gaskets, clamps, torque wrench
• If the catalytic converter is damaged or clogged, it will need replacement.
• Disconnect the exhaust pipe from the catalytic converter by removing bolts or clamps.
• If required, cut the exhaust pipe with a cutting tool.
• Install the new catalytic converter with new gaskets and tighten bolts to the specified torque (usually around 40 lb-ft).
• Reconnect the exhaust pipe and secure it with clamps or bolts.

4. Clear Codes and Test

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature, then monitor the engine for any new codes.