how to fix Honda Pilot Third Generation (2016-present) P0420 code

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the battery to prevent electrical issues.
• Raise the vehicle securely on jack stands and ensure the exhaust system is cool.

2. Inspect and Replace O2 Sensors

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) O2 sensors.
2. Use a wrench to carefully remove the O2 sensors from the exhaust system.
3. Inspect the sensors for damage or excessive wear.
4. If necessary, install new O2 sensors:
   • Apply anti-seize compound to the threads of the new sensors.
   • Torque to manufacturer specifications (usually around 30 lb-ft).
5. Reconnect the electrical connectors.

3. Check and Replace Catalytic Converter (if necessary)

1. If the O2 sensors are functional and the P0420 code persists, check the catalytic converter:
   • Inspect for physical damage or excessive rust.
   • If damaged, remove the catalytic converter by unbolting it from the exhaust system.
2. Install the new catalytic converter:
   • Place the new converter in position.
   • Align and secure it with bolts, torquing them to manufacturer specifications (usually around 30-40 lb-ft).
3. Reconnect any necessary exhaust hangers.

4. Final Steps

1. Reconnect the battery.
2. Clear the P0420 code using the OBD-II scanner.
3. Start the engine and allow it to reach operating temperature.