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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the vehicle battery to ensure safety during electrical repairs.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors:
   • Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Remove the Oxygen Sensors:
   • Use an oxygen sensor socket to carefully unscrew the sensors from their respective locations.
   • Disconnect the wiring harness from each sensor.
3. Install New Oxygen Sensors:
   • Apply anti-seize compound on the threads of the new sensors.
   • Install the new sensors in the same location, tightening to the manufacturer's specifications (typically 30 lb-ft).
   • Reconnect the wiring harness securely.

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

1. Remove Exhaust Components:
   • If the catalytic converter is suspected faulty, unbolt the exhaust pipes connected to it using a socket set.
2. Inspect the Catalytic Converter:
   • Check for physical damage, rattling sounds, or signs of clogging.
3. Install New Catalytic Converter:
   • Position the new catalytic converter and bolt it in place, ensuring proper alignment.
   • Use a torque wrench to tighten bolts to the specified torque values (usually around 30-45 lb-ft depending on the model).

4. Reset the Engine Control Module (ECM)

1. Reconnect the Battery:
   • Reconnect the vehicle battery terminals.
2. Clear the Codes:
   • Use the OBD-II scanner to clear the P0420 code from the ECM.
3. Start the Engine:
   • Run the engine to ensure no new codes appear and that the check engine light remains off.