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

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use penetrating oil on the sensor threads if they appear rusted or corroded.
  3. Remove the upstream oxygen sensor using the O2 sensor socket.
  4. Install the new oxygen sensor, tightening it to manufacturer specifications (usually around 30 lb-ft).
  5. Repeat steps 3-4 for the downstream oxygen sensor if needed.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust pipe cutter or saw, gasket scraper.
• Sub-steps:
  1. Remove the exhaust heat shield if applicable.
  2. Use a socket set to unbolt the catalytic converter from the exhaust pipes, taking care to note the positioning of any gaskets.
  3. Inspect the old catalytic converter for damage or blockage.
  4. Clean the mounting surfaces and install the new catalytic converter, ensuring proper gasket placement.
  5. Torque the bolts to the manufacturer's specifications (typically around 30 lb-ft).

4. Reset the Check Engine Light

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code and any other stored codes.