how to fix P0420 code in Honda Accord 9th Generation (2013-2017)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool completely before starting any work.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Use a socket wrench to remove the upstream oxygen sensor.
   • Tools Required: O2 sensor socket, ratchet, torque wrench.
3. Install the new upstream oxygen sensor and torque it to the manufacturer's specifications (typically around 30 ft-lbs).
4. Repeat the process for the downstream oxygen sensor if it is also faulty.

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

1. Remove the exhaust pipe connected to the catalytic converter using a socket set.
   • Tools Required: Socket set, penetrating oil.
2. Unbolt the catalytic converter from the exhaust manifold and remove it from the vehicle.
3. Install the new catalytic converter and secure it using new gaskets and bolts as per manufacturer specifications.
4. Reattach the exhaust pipe and ensure all connections are tight.

4. Reconnect Battery and Clear Codes

1. Reconnect the vehicle's battery.
2. Use the OBD-II scanner to clear the P0420 code from the system.
3. Start the engine and let it idle for a few minutes.