how to fix Honda CR-V Sixth Generation (2023-present) P0420 code

Solution

1. Preparation

• Gather tools and parts required.
• Park the vehicle on a level surface and ensure the engine is cool.
• Disconnect the negative battery terminal.

2. Inspect Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Use a socket wrench to remove both sensors.
  3. Inspect the sensors for wear or contamination; replace if necessary.
• Tools Required: Oxygen sensor socket, socket wrench

3. Check for Exhaust Leaks

• Sub-steps:
  1. Visually inspect the exhaust system from the engine to the tailpipe for any signs of leaks or damage.
  2. Start the engine and listen for any unusual sounds indicating a leak.
  3. Use a smoke machine or soapy water to detect small leaks.
• Tools Required: Smoke machine (optional), soapy water

4. Test Catalytic Converter

• Sub-steps:
  1. Start the engine and allow it to reach normal operating temperature.
  2. Use a temperature probe to measure the inlet temperature of the catalytic converter.
  3. Measure the outlet temperature; it should be significantly higher than the inlet temperature if the converter is functioning properly.
• Tools Required: Infrared thermometer

5. Replace Catalytic Converter (if needed)

• Sub-steps:
  1. If the catalytic converter is faulty, raise the vehicle safely on jack stands.
  2. Remove the exhaust system components connected to the catalytic converter.
  3. Unbolt the catalytic converter from the exhaust manifold and exhaust pipe.
  4. Install the new catalytic converter and secure it with the correct torque specifications.
  5. Reconnect any exhaust components removed earlier.
• Tools Required: Socket set, torque wrench

6. Reinstall Oxygen Sensors

• Sub-steps:
  1. Apply anti-seize compound to the threads of the new oxygen sensors.
  2. Install the upstream and downstream sensors and tighten them to manufacturer specifications.
• Tools Required: Oxygen sensor socket, torque wrench