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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Remove the oxygen sensor:
   • Use an oxygen sensor socket to carefully unscrew the upstream (pre-catalytic) oxygen sensor.
   • Disconnect the electrical connector.
2. Install new oxygen sensor:
   • Apply anti-seize compound to the threads of the new oxygen sensor (if required).
   • Screw in the sensor by hand to avoid cross-threading, then tighten to the manufacturer's specified torque (usually around 30 lb-ft).
   • Reconnect the electrical connector.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove exhaust components:
   • Use a socket set to unbolt the exhaust pipes connected to the catalytic converter.
   • Support the exhaust system with jack stands if necessary.
2. Remove the catalytic converter:
   • Detach the catalytic converter from its mounting brackets and remove from the vehicle.
3. Install the new catalytic converter:
   • Place the new converter in position and secure it with the bolts and gaskets as per the manufacturer's specifications.
   • Tighten bolts to the appropriate torque values (typically 30-40 lb-ft).

4. Clear the P0420 Code

• Reconnect the vehicle's battery.
• Use an OBD-II scanner to clear the stored P0420 trouble code.
• Perform a test drive to allow the vehicle’s systems to recalibrate.