how to fix P0420 code on my Honda Pilot YF3 (2016-2022)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety during 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 upstream oxygen sensor:
   • Use a socket wrench with an oxygen sensor socket.
   • Disconnect the electrical connector.
   • Unscrew the sensor and set it aside.
3. Install the new upstream oxygen sensor:
   • Apply anti-seize compound to the threads of the new sensor.
   • Screw in the new sensor and tighten to the manufacturer’s specifications (usually around 30 lb-ft).
   • Reconnect the electrical connector.
4. Repeat for the downstream oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter

1. Remove the exhaust system components: Depending on your vehicle's configuration, you may need to remove the exhaust pipe or heat shields.
2. Unbolt the catalytic converter: Use a socket set to remove the bolts securing the catalytic converter to the exhaust system.
3. Inspect the old catalytic converter: Check for signs of clogging or damage. If it's damaged or excessively dirty, it should be replaced.
4. Install the new catalytic converter:
   • Position the new catalytic converter in place.
   • Secure it with the bolts, tightening them to the specified torque (usually around 25 lb-ft).
5. Reattach any removed exhaust components.

4. Final Assembly

• Reconnect any heat shields or brackets that were removed.
• Reconnect the negative battery terminal.