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

Solution

1. Preparation

• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Gather necessary tools and parts.
• Disconnect the battery to avoid any electrical issues.

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 Sensors:
   • Use a socket wrench to unscrew the oxygen sensors from the exhaust manifold and catalytic converter.
   • Carefully disconnect the wiring harness from each sensor.
3. Install New Sensors:
   • Apply anti-seize compound to the threads of the new oxygen sensors.
   • Screw in the new sensors and connect the wiring harness securely.
   • Torque the sensors to the manufacturer's specifications (typically around 30 Nm).

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

1. Remove Exhaust Components:
   • Use a socket set to unfasten the bolts securing the catalytic converter to the exhaust system.
   • Carefully lower the catalytic converter from the vehicle.
2. Inspect the Old Catalytic Converter:
   • Check for any signs of damage, such as dents or rattles that indicate internal failure.
3. Install New Catalytic Converter:
   • Position the new catalytic converter in place and secure it with the bolts.
   • Ensure all gaskets are in good condition; replace if necessary.
   • Torque the bolts to the manufacturer's specifications (typically around 40 Nm).

4. Reconnect the Battery

• Reconnect the negative battery terminal and ensure it is securely fastened.

5. Clear the Codes

• Use an OBD-II scanner to clear the P0420 code from the vehicle's memory.