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

Solution

1. Preparation

• Gather all tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to ensure safety during the repair.

2. Inspect and Replace Oxygen Sensors (if faulty)

• Sub-steps:
  1. Identify the location of the upstream and downstream oxygen sensors.
  2. Use an O2 sensor socket to carefully unscrew the faulty sensor(s) from the exhaust system.
  3. Install the new oxygen sensor(s) and torque to the manufacturer's specifications (typically around 30 ft-lbs).
  4. Reconnect the sensor connectors ensuring a secure fit.

3. Check and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove the exhaust pipes connected to the catalytic converter, using a socket set.
  2. Unbolt the catalytic converter from its mounting points.
  3. Inspect the old catalytic converter for signs of clogging or damage.
  4. Install the new catalytic converter, ensuring all gaskets are in place and bolts are torqued to specifications (typically around 25 ft-lbs).
  5. Reconnect the exhaust pipes securely.

4. Reset the Engine Control Unit (ECU)

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Using an OBD-II scanner, clear the P0420 code from the ECU.
  3. Start the engine and allow it to reach operating temperature.