how to fix the P0420 code on my Honda Accord 9th Generation (2013-2017)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal.
• Raise the vehicle and secure it on jack stands.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: The upstream sensor is typically located before the catalytic converter, and the downstream sensor is after it.
2. Remove the upstream oxygen sensor:
   • Use an oxygen sensor socket or wrench to unscrew it.
3. Install the new upstream oxygen sensor:
   • Apply anti-seize compound on the threads of the new sensor.
   • Torque to manufacturer specifications (usually around 30-35 ft-lbs).
4. Repeat for the downstream oxygen sensor, if necessary.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Check the catalytic converter for physical damage or blockage.
2. Remove the catalytic converter:
   • Unbolt the exhaust flanges using the appropriate socket and ratchet.
   • Remove any hangers or brackets holding the catalytic converter.
3. Install the new catalytic converter:
   • Position it and secure it with bolts to the exhaust flanges.
   • Torque bolts to manufacturer's specifications.
4. Reinstall any hangers or brackets that were removed.

4. Clear Codes and Test Drive

1. Reconnect the negative battery terminal.
2. Use an OBD-II scanner to clear the P0420 code.
3. Conduct a test drive to ensure the engine runs smoothly and check for any codes after driving.