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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent any electrical issues.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench, multimeter.
• Remove the upstream (pre-catalytic) oxygen sensor using the O2 sensor socket.
• Inspect the sensor’s connector and wiring for damage.
• If the sensor is faulty, install the new upstream oxygen sensor by aligning it correctly and tightening it to the manufacturer's specified torque (usually around 30 ft-lbs).
• Repeat for the downstream (post-catalytic) oxygen sensor if it was found to be faulty.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, cutting tool (if necessary), exhaust gasket.
• Locate the catalytic converter and inspect it for physical damage or signs of clogging.
• If replacement is necessary, unbolt the catalytic converter from the exhaust system while supporting it to avoid injury.
• Install the new catalytic converter, ensuring proper alignment and secure it with bolts to the specified torque.
• Replace any gaskets to prevent exhaust leaks.

4. Clear Codes and Test Drive

• Reconnect the battery and use an OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to warm up, then take the vehicle for a test drive to ensure all systems are functioning properly.