how to fix P0420 code on Ford F-150 Fourteenth Generation (2021-present)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, jack, jack stands.
• Ensure the vehicle is parked on a level surface. Disconnect the battery to prevent electrical shorts while working on the vehicle.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors:
   • Identify the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Remove the Oxygen Sensors:
   • Use a socket wrench to unscrew the oxygen sensors from the exhaust system.
   • Be cautious as they may be hot if the vehicle was recently used.
3. Test the Sensors:
   • Using a multimeter, check the voltage output of the upstream sensor. It should fluctuate between 0.1 and 0.9 volts.
   • If the readings are outside this range or if the sensor is unresponsive, replace it.
4. Install New Sensors:
   • Apply anti-seize compound on the threads of the new sensors.
   • Install the new oxygen sensors and tighten them to the manufacturer's specifications (typically around 30 lb-ft).

3. Inspect and Replace Catalytic Converter (if necessary)

1. Inspect for Damage:
   • Check the catalytic converter for signs of physical damage or blockage.
2. Remove the Catalytic Converter:
   • Support the exhaust system with a jack and remove the bolts securing the catalytic converter.
   • Carefully disconnect it from the exhaust pipes.
3. Install New Catalytic Converter:
   • Position the new catalytic converter and secure it with the bolts.
   • Torque the bolts to the specified value (usually around 30-40 lb-ft).

4. Reset the ECU

1. Reconnect Battery:
   • Reconnect the negative terminal of the battery.
2. Clear the Codes:
   • Use the OBD-II scanner to clear the P0420 code from the ECU.