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

Solution

1. Preparation

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

2. Replace Oxygen Sensors

1. Locate the Sensors

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

2. Remove the Sensors

   • Using an O2 sensor socket, carefully unscrew the sensors from their respective locations.
   • Use penetrating oil if the sensors are stuck.

3. Install New Sensors

   • Apply anti-seize compound to the threads of the new sensors (if recommended).
   • Screw in the new sensors by hand to avoid cross-threading, then tighten to manufacturer specifications (usually around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove Exhaust Components

   • If the catalytic converter is suspected to be faulty, remove any exhaust components connected to it using a socket set.
   • Carefully support the exhaust system to avoid damage.

2. Inspect the Catalytic Converter

   • Look for signs of physical damage or blockage. If it appears damaged or clogged, proceed to replace it.

3. Install New Catalytic Converter

   • Position the new catalytic converter and secure it to the exhaust system.
   • Tighten all connections to manufacturer specifications.

4. Clear Error Codes

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 error code.

5. Test the Repair

• Start the vehicle and allow it to reach operating temperature.
• Check for the check engine light and monitor performance.