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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative terminal of the battery to prevent electrical shorts while working.
• Allow the exhaust system to cool down before starting.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench
• Remove the upstream oxygen sensor from the exhaust manifold.
  • Ensure the engine is cool.
  • Use the O2 sensor socket to unscrew the sensor.
• Install the new upstream oxygen sensor and torque it to the manufacturer's specifications (usually around 30 ft-lbs).
• Repeat for the downstream oxygen sensor if testing indicated it is faulty.

3. Inspect and Replace the Catalytic Converter (if needed)

• Tools Required: Wrench set, exhaust pipe cutter, gasket scraper
• Remove the exhaust pipe sections leading to and from the catalytic converter.
  • If the converter is bolted, use the appropriate wrench to loosen bolts.
  • If it's welded, use an exhaust pipe cutter to remove it.
• Clean the mounting surfaces of the exhaust system to ensure a proper seal with the new catalytic converter.
• Install the new catalytic converter, making sure to align it correctly with the exhaust system.
• Secure all bolts to the specified torque (usually around 25-35 ft-lbs).

4. Reconnect Battery and Clear Codes

• Reconnect the negative terminal of the battery.
• Use the OBD-II scanner to clear the trouble codes from the system.
• Start the engine and let it idle for a few minutes.