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

Solution

1. Preparation

• Gather the necessary tools and parts.
• Disconnect the battery to prevent electrical shock.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors.
2. Remove the electrical connectors from both sensors.
3. Use a socket wrench to unscrew the sensors from the exhaust pipe.
4. Install new oxygen sensors, ensuring they are tightened to the manufacturer's torque specifications (typically around 30 lb-ft).
5. Reconnect the electrical connectors.

3. Inspect and Repair Exhaust System

1. Visually inspect the entire exhaust system, including the catalytic converter, for leaks or damage.
2. If leaks are found, use exhaust repair tape or replace the damaged section.
3. Ensure all connections are tight and secure.

4. Test Catalytic Converter

1. Use an infrared thermometer to measure the inlet temperature of the catalytic converter.
2. Measure the outlet temperature of the catalytic converter.
3. The outlet temperature should be at least 100°F higher than the inlet. If not, the catalytic converter may need replacement.

5. Replace Catalytic Converter (if necessary)

1. Disconnect the battery again.
2. Remove any heat shields covering the catalytic converter.
3. Unscrew the bolts securing the catalytic converter to the exhaust system.
4. Install the new catalytic converter, ensuring all gaskets are replaced.
5. Tighten all bolts to the manufacturer's specifications (typically around 30-40 lb-ft).
6. Reconnect the battery.