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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, safety glasses, gloves.
• Ensure the vehicle is parked on a flat surface with the engine off and cooled down. Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Using the socket set, carefully remove both oxygen sensors.
  3. Inspect the sensors for contamination or damage. If faulty, replace with new OEM sensors.
  4. Apply anti-seize compound on the threads of the new sensors, then install and torque to manufacturer specifications (usually around 30 Nm).

3. Inspect Catalytic Converter

• Sub-steps:
  1. Visually inspect the catalytic converter for physical damage or signs of overheating (blistering or discolouration).
  2. If damage is found, prepare to replace the catalytic converter.
  3. Remove the catalytic converter from the exhaust system using the socket set. Ensure to support the exhaust system to prevent strain during removal.

4. Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Install the new catalytic converter by aligning it with the exhaust system connections.
  2. Secure with new gaskets and bolts, torquing to manufacturer specifications.
  3. Reconnect any O2 sensors that were disconnected during removal.

5. Reconnect Battery and Clear Codes

• Reconnect the vehicle's battery terminals securely.
• Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.