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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle's battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:

   • Locate the upstream oxygen sensor (usually near the exhaust manifold).
   • Use an oxygen sensor socket to carefully unscrew and remove the sensor.

2. Install a new upstream oxygen sensor:

   • Apply anti-seize compound to the threads of the new sensor.
   • Install the new sensor by threading it into place and tightening it to the manufacturer's torque specifications (typically around 30-40 ft-lbs).

3. Remove the downstream oxygen sensor (if necessary):

   • Repeat the removal process for the downstream oxygen sensor (located after the catalytic converter).

4. Install a new downstream oxygen sensor:

   • Follow the same procedure to install the new sensor.

3. Inspect and Replace Catalytic Converter (if needed)

1. Remove the catalytic converter:
   • Loosen and remove the bolts securing the catalytic converter to the exhaust system using a socket set and breaker bar.
   • Carefully lower the catalytic converter from its mounting location.
2. Inspect the old catalytic converter:
   • Check for any signs of physical damage, melting, or clogging.
3. Install a new catalytic converter:
   • Position the new catalytic converter in place and secure it with the bolts. Torque the bolts to the manufacturer's specifications (usually around 25-30 ft-lbs).

4. Reconnect Battery and Clear Codes

• Reconnect the vehicle's battery.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.