how to fix P0420 code in Honda Accord 10th Generation (2018-2022)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the vehicle to cool down completely before starting work.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Use an O2 sensor socket to carefully remove the sensors.
3. Inspect the sensor connectors for corrosion or damage; clean or replace as necessary.
4. Install new oxygen sensors, ensuring they are torqued to manufacturer specifications (typically around 30 lb-ft).
5. Reconnect the wiring harness securely.

3. Check and Replace the Catalytic Converter

1. Inspect the catalytic converter for visible signs of damage, such as dents or rust.
2. If damaged, use a socket set to remove the bolts securing the catalytic converter to the exhaust system.
3. Disconnect any additional mounts or brackets holding the converter in place.
4. Install the new catalytic converter, ensuring proper alignment and torque specifications for the bolts (around 30-50 lb-ft depending on application).
5. Reconnect any mounts or brackets and ensure a secure fit.

4. Reset the Engine Control Module (ECM)

1. Reconnect the negative battery terminal.
2. Use the OBD-II scanner to clear the P0420 code from the ECM.
3. Allow the vehicle to idle for a few minutes to verify the reset.