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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent any electrical issues during the repair.

2. Inspect and Test O2 Sensors

• Tools Required: OBD-II scanner, multimeter.
• Remove the connectors from the upstream and downstream O2 sensors.
• Using a multimeter, test the O2 sensors for proper voltage output.
  • Upstream O2 sensor should fluctuate between 0.1 to 0.9 volts.
  • Downstream O2 sensor should have a stable voltage around 0.5 volts.
• Replace any faulty O2 sensors.

3. Examine the Catalytic Converter

• Tools Required: Wrench set, jack and jack stands.
• Raise the vehicle and securely support it with jack stands.
• Inspect the catalytic converter for signs of damage, such as dents, rust, or physical blockages.
• If the catalytic converter is clogged or damaged, remove it:
  • Remove the bolts attaching the catalytic converter to the exhaust pipes using a wrench.
  • Carefully detach the catalytic converter from the exhaust system and replace it with a new unit.

4. Reassembly and Connection

• Reinstall the new catalytic converter and tighten the bolts to manufacturer specifications (usually around 25-30 ft-lbs).
• Reconnect any O2 sensors and other components that were disconnected.
• Ensure all connections are secure.

5. Clear Codes and Test Drive

• Tools Required: OBD-II scanner.
• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the engine control module (ECM).
• Start the vehicle and take it for a test drive to monitor for any reoccurrence of the code.