how to fix P0420 code in Honda Accord 9th Generation (2013-2017)

Solution

1. Preparation

• Gather tools and parts.
• Ensure the vehicle is parked on a level surface.
• Disconnect the battery to prevent any electrical issues.

Tools Required:

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

2. Inspect and Replace O2 Sensors (if necessary)

1. Locate Sensors:

   • Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) O2 sensors.

2. Remove Sensors:

   • Use a socket wrench to carefully unscrew the O2 sensors from their respective locations.
   • Be cautious of the wire harness connected to the sensors.

3. Install New Sensors:

   • Apply anti-seize compound to the threads of the new sensors.
   • Screw the new O2 sensors into place and tighten to the manufacturer’s specified torque (typically around 30 lb-ft).

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove Exhaust Components:

   • Use a socket set to disconnect the exhaust pipes from the catalytic converter.
   • Support the exhaust system and remove any hangers to free the converter.

2. Inspect Catalytic Converter:

   • Check for physical damage, blockage, or excessive buildup.
   • If damaged, replace with a new catalytic converter.

3. Install New Catalytic Converter:

   • Position the new catalytic converter and align it with the exhaust system.
   • Reattach the exhaust pipes and secure them with bolts, torqueing to manufacturer specifications (usually around 25-30 lb-ft).

4. Reconnect O2 Sensors:

   • Reconnect the wiring harness to both O2 sensors.

4. Reset the Engine Control Module (ECM)

1. Reconnect Battery:

   • Reconnect the battery terminals, ensuring a secure connection.

2. Clear Codes:

   • Use the OBD-II scanner to clear the P0420 code from the ECM.