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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to avoid electrical issues.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor:
  1. Locate the upstream O2 sensor near the exhaust manifold.
  2. Use an O2 sensor socket to carefully unscrew the sensor.
  3. Install the new O2 sensor and torque it to the manufacturer's specification (typically around 33 lb-ft).
• Repeat for the downstream oxygen sensor if it shows signs of failure.

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

• Tools Required: Socket set, torque wrench, exhaust gasket
• Remove the catalytic converter:
  1. Loosen the bolts securing the catalytic converter to the exhaust manifold and exhaust pipe using a socket set.
  2. Carefully detach the converter from the exhaust system.
  3. Inspect gaskets and replace if damaged.
• Install the new catalytic converter:
  1. Align the new converter with the exhaust system.
  2. Secure it with bolts and torque them to the manufacturer's specifications.

4. Clear Fault Codes

• Use the OBD-II scanner to clear the P0420 code and any other codes present in the system.

5. Reconnect Battery

• Reconnect the negative battery terminal.