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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the vehicle to cool down completely.

2. Inspect Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
• Remove the upstream and downstream oxygen sensors using an oxygen sensor socket or wrench.
• Inspect the sensor tips for contamination or damage. Clean if necessary.
• Test the sensors with a multimeter:
  • For the upstream sensor: Check for a fluctuating voltage between 0.1V and 0.9V during idle.
  • For the downstream sensor: Check for a steady voltage around 0.5V.
• Replace any faulty oxygen sensors with OEM replacements.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torch wrench, exhaust hanger removal tool
• Remove any heat shields covering the catalytic converter if applicable.
• Unbolt the catalytic converter from the exhaust system using the socket set.
• Inspect the catalytic converter for signs of clogging or damage (e.g., rattling noise, discoloration).
• If faulty, replace it with a new catalytic converter that meets OEM specifications.
• Reinstall the catalytic converter and heat shields, tightening bolts to the manufacturer's specified torque values.

4. Clear Codes and Test

• Reconnect the battery.
• Use an OBD-II scanner to clear the P0420 code.
• Start the engine and let it reach operating temperature.
• Monitor the performance of the oxygen sensors again to ensure they are functioning correctly.