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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Test Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
• Remove the upstream and downstream oxygen sensors using an O2 sensor socket.
• Use the multimeter to check the voltage output of the upstream sensor while the engine is running; it should fluctuate between 0.1 to 0.9 volts.
• If the upstream sensor is faulty, replace it with a new one.

3. Check Catalytic Converter

• Tools Required: Thermometer, socket set
• Start the engine and let it warm up to operating temperature.
• Measure the temperature of the exhaust before the catalytic converter and after it using a thermometer.
• If the temperature difference is less than 100°F (37.7°C), the catalytic converter may be failing and should be replaced.

4. Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket
• Lift the vehicle using a jack and secure it with jack stands.
• Remove the catalytic converter from the exhaust system by unbolting the flanges using a socket set.
• Install the new catalytic converter with a new gasket, ensuring bolts are torqued to manufacturer specifications (usually around 30-40 lb-ft).
• Reconnect the oxygen sensors if they were removed.

5. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.