how to fix P0420 code on Ford F-150 13th Generation (2015-2020)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Remove the negative battery terminal.
   • Use a wrench to disconnect the negative cable.
2. Locate the oxygen sensors.
   • Identify the upstream (pre-cat) and downstream (post-cat) sensors.
3. Test the oxygen sensors.
   • Using a multimeter, measure the voltage output. Replace any sensor that shows incorrect readings.
4. Remove the faulty oxygen sensor.
   • Use an oxygen sensor socket to unscrew the sensor.
5. Install the new oxygen sensor.
   • Apply anti-seize compound to the threads, then screw in the new sensor and torque to manufacturer specifications.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Check for physical damage.
   • Inspect the catalytic converter for dents, cracks, or rattling noises.
2. Remove the catalytic converter.
   • Loosen the bolts at both the front and rear of the converter using a socket set.
3. Install the new catalytic converter.
   • Position the new converter and secure it with bolts. Torque to manufacturer specifications.
4. Reconnect the exhaust system.
   • Ensure all connections are secure and there are no leaks.

4. Clear the Codes and Test Drive

1. Reconnect the battery terminal.
   • Reattach the negative cable and tighten securely.
2. Clear the error codes.
   • Use the OBD-II scanner to erase the P0420 code.
3. Test drive the vehicle.
   • Monitor the engine performance for any reoccurrence of the check engine light.