how to fix P0420 code on Ford Explorer Fifth Generation (2011-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface with the engine off and cool.

2. Inspect and Replace Oxygen Sensors

1. Remove the negative battery cable to avoid any electrical shorts.
2. Use an OBD-II scanner to clear the P0420 code.
3. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
4. Use a socket wrench to remove the upstream oxygen sensor. Note the installation orientation for reassembly.
5. Install the new upstream oxygen sensor, tightening it to manufacturer specifications (typically around 30 lb-ft).
6. Repeat the process for the downstream oxygen sensor if needed.

3. Examine and Replace the Catalytic Converter

1. Inspect the catalytic converter for any signs of damage or blockage.
2. If replacement is necessary, use a socket set to remove the exhaust pipes connected to the catalytic converter.
3. Install the new catalytic converter, ensuring proper alignment and sealing.
4. Torque the fastening bolts according to manufacturer specifications (usually around 30 lb-ft).
5. Reconnect the exhaust system and any heat shields removed during the process.

4. Final Checks

1. Reconnect the negative battery cable.
2. Start the engine and let it idle for a few minutes.
3. Use the OBD-II scanner to verify that the P0420 code does not reappear.