how to fix the P0420 code on my Honda Accord 10th Generation (2018-2022)

Solution

1. Preparation

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

Tools Required:

• OBD-II scanner
• Multimeter
• Socket set
• Torque wrench
• Exhaust pipe cutter (if necessary)

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream (before the catalytic converter) and downstream (after the catalytic converter) oxygen sensors.
2. Unplug the connectors: Carefully disconnect the electrical connectors from both oxygen sensors.
3. Remove the sensors: Use a socket wrench to unscrew the sensors from the exhaust pipe.
4. Test the sensors: Use a multimeter to check the resistance and performance of the sensors. Replace if they are out of specifications.
5. Install new sensors: Screw the new oxygen sensors into place and reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove exhaust components: If the catalytic converter needs replacement, first remove any exhaust components that obstruct access, using an exhaust pipe cutter if necessary.
2. Unbolt the catalytic converter: Use a socket set to unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
3. Install the new catalytic converter: Position the new catalytic converter and secure it with bolts to the exhaust manifold and exhaust pipe. Torque to manufacturer specifications.
4. Reconnect exhaust components: Reinstall any exhaust components that were removed, ensuring all connections are secure.

4. Final Steps

1. Reconnect the battery: Reattach the negative battery terminal.
2. Clear the error codes: Use an OBD-II scanner to clear the P0420 code from the vehicle’s computer.
3. Test drive the vehicle: Monitor for any reoccurrence of the check engine light and ensure proper operation.