how to fix P0420 code on Ford Explorer Sixth Generation (2020-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery negative terminal for safety.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:

   • Using an oxygen sensor socket, carefully unscrew the sensor from the exhaust manifold.
   • Check the wiring harness for any damage.

2. Install the new upstream oxygen sensor:

   • Apply anti-seize compound on the threads of the new sensor.
   • Install the new sensor and tighten it to manufacturer specifications (usually around 30 Nm or 22 lb-ft).

3. Repeat for the downstream oxygen sensor if necessary:

   • Follow the same steps as above for the downstream sensor located after the catalytic converter.

3. Inspect and Replace the Catalytic Converter

1. Remove the exhaust pipe connected to the catalytic converter:

   • Use a socket set to unbolt the flanges connecting the exhaust pipe to the catalytic converter.
   • Remove any hangers or brackets securing the exhaust system.

2. Install the new catalytic converter:

   • Position the new catalytic converter in place, ensuring proper alignment with the exhaust system.
   • Torque the bolts to manufacturer specifications (typically between 40-50 Nm or 30-37 lb-ft).

3. Reattach the exhaust pipe:

   • Reconnect the exhaust pipe to the catalytic converter, ensuring a tight seal.
   • Reinstall any hangers or brackets removed earlier.

4. Reconnect Battery and Clear Codes

1. Reconnect the battery:

   • Connect the negative terminal securely.

2. Clear the error codes:

   • Use the OBD-II scanner to erase the P0420 code from the vehicle's computer.

5. Test Drive

1. Perform a test drive:
   • Drive the vehicle for at least 20 minutes under various conditions to ensure proper operation and monitor for any return of the check engine light.