how to fix the P0420 code in my Honda CR-V Fifth Generation (2017-2022)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety during repairs.
• Raise the vehicle securely on jack stands if needed.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil
• Inspect the upstream oxygen sensor (before the catalytic converter) for functionality.
• If faulty, use penetrating oil to loosen the sensor. Disconnect the electrical connector and remove the sensor using the O2 sensor socket.
• Install the new sensor, tightening it to manufacturer specifications (usually around 30 ft-lbs). Reconnect the electrical connector.

3. Examine or Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket
• Check the catalytic converter for signs of damage or clogging. If exhaust flow is restricted, replacement may be necessary.
• Remove the bolts securing the catalytic converter to the exhaust system. Use a socket set for this task.
• Carefully detach the catalytic converter, ensuring to replace any gaskets as needed.
• Install the new catalytic converter, tightening the bolts to the specified torque (consult manufacturer specifications for exact values).

4. Reset the ECU

• Reconnect the negative battery terminal.
• Use an OBD-II scanner to clear the P0420 code from the vehicle's ECU.