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

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the negative battery terminal to ensure safety.
• Allow the vehicle to cool down if it has been running.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter.
• Disconnect the upstream and downstream oxygen sensors.
• Use a multimeter to check the voltage output of the upstream sensor; it should fluctuate between 0.1V and 0.9V.
• If the readings are outside this range, replace the upstream oxygen sensor.
• Reconnect the new sensor and repeat the process for the downstream sensor, replacing it if necessary.

3. Check and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if necessary).
• Inspect the catalytic converter for physical damage or clogs.
• If necessary, remove the catalytic converter by unbolting it from the exhaust system. Use an exhaust pipe cutter if the bolts are rusted or broken.
• Install the new catalytic converter, securing it to the exhaust system as per manufacturer specifications (typically 30-40 ft-lbs torque).
• Ensure proper alignment of exhaust pipes to avoid stress on the new converter.

4. Clear Codes and Test Drive

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
• Test drive the vehicle for at least 20 minutes to allow the system to monitor for any issues.