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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to ensure safety during work.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Multimeter
• Safety glasses
• Gloves

2. Inspect and Test O2 Sensors

• Remove the upstream and downstream oxygen sensors using a socket.
• Test the upstream O2 sensor for voltage and response to throttle input using a multimeter.
• If the sensor does not respond correctly, replace it.

3. Replace the Catalytic Converter (if necessary)

• 3.1. Remove Exhaust Components:

  • Remove any heat shields or brackets securing the catalytic converter.
  • Use a socket set to unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.

• 3.2. Install New Catalytic Converter:

  • Position the new catalytic converter in place.
  • Tighten the bolts to the manufacturer's specified torque (usually around 30-40 lb-ft, but check specifications).

• 3.3. Reinstall O2 Sensors:

  • Reinstall the upstream and downstream O2 sensors into the new catalytic converter.
  • Ensure they are tightened securely but do not overtighten.

4. Reconnect Battery and Clear Codes

• Reconnect the battery.
• Use an OBD-II scanner to clear the P0420 code from the vehicle's computer.