how to fix P0420 code on Honda Accord Eleventh Generation (2023-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Multimeter
• Jack and jack stands

2. Inspect and Replace Oxygen Sensors

• Remove the upstream and downstream oxygen sensors.
• Use a multimeter to test the sensors for proper voltage and response to exhaust conditions.
• If faulty, replace with OEM or quality aftermarket sensors.

3. Inspect and Replace Catalytic Converter

• If the catalytic converter is damaged or blocked, remove it from the exhaust system.
• Inspect the exhaust manifold and pipe connections for integrity.
• Install a new catalytic converter, ensuring it matches the original specifications.
• Torque the bolts to the manufacturer’s specification.

4. Clear Codes and Test Drive

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's system.
• Test drive the vehicle for at least 30 minutes to allow the system to monitor the catalytic converter's performance.