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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal.
• Raise the vehicle safely on jack stands to access the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:

   • Use an oxygen sensor socket to unscrew the sensor from the exhaust manifold.
   • Disconnect the electrical connector.

2. Install the new upstream oxygen sensor:

   • Apply anti-seize compound to the threads of the new sensor.
   • Screw in the sensor and connect the electrical connector.

3. Repeat for the downstream oxygen sensor:

   • Remove and replace the downstream sensor using the same method.

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

1. Check for physical damage:

   • Look for dents, cracks, or rust on the catalytic converter.

2. Remove the catalytic converter:

   • Unbolt the exhaust flanges using a socket set.
   • Carefully detach the converter from the exhaust system.

3. Install the new catalytic converter:

   • Position the new converter in place.
   • Bolt it securely to the exhaust flanges using the manufacturer-recommended torque specifications (typically around 30-40 lb-ft).

4. Reassemble Exhaust System

• Ensure all bolts are tightened to specified torque.
• Reattach any heat shields or hangers that were removed during the process.

5. Reset the Engine Control Module (ECM)

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the ECM.