how to fix P0420 code on Honda CR-V Fifth Generation (2017-2022)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is off.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (before catalytic converter) and downstream (after catalytic converter) oxygen sensors.
2. Use an O2 sensor socket to remove the upstream oxygen sensor.
   • Tools Required: O2 sensor socket, ratchet, and extension.
3. Install the new upstream oxygen sensor, ensuring to torque it to the manufacturer’s specifications (typically around 30-40 Nm).
4. Repeat the removal and installation process for the downstream oxygen sensor if it is faulty.

3. Check and Replace Catalytic Converter (if necessary)

1. If previous steps do not resolve the issue, inspect the catalytic converter for blockage or damage.
2. Remove the bolts securing the catalytic converter to the exhaust manifold and the exhaust pipe.
   • Tools Required: Socket set and possibly a breaker bar for stuck bolts.
3. Carefully detach the catalytic converter from the exhaust system.
4. Install the new catalytic converter, ensuring proper alignment and securing it with the bolts. Torque bolts to manufacturer's specifications.
5. Reconnect all removed oxygen sensors and ensure all electrical connections are secure.

4. Reset the ECU

1. Reconnect the negative battery terminal.
2. Use an OBD-II scanner to clear the P0420 code from the ECU.
3. Start the engine and allow it to run for a few minutes to ensure there are no additional codes.