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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, digital thermometer, multimeter, safety glasses, gloves.
• Ensure the vehicle is parked on a level surface, and the engine is off and cool.

2. Inspect and Repair Exhaust Leaks

• Sub-steps:
  1. Visually inspect the exhaust system from the engine to the tailpipe for any signs of leaks or damage.
  2. Use a smoke machine or soapy water to identify small leaks, especially around joints and gaskets.
  3. Repair or replace any damaged parts, including gaskets or exhaust pipes, as necessary.

3. Test and Replace Oxygen Sensors

• Sub-steps:
  1. Disconnect the electrical connectors from the upstream and downstream oxygen sensors.
  2. Use a multimeter to test the voltage output of the sensors while the engine is running; the upstream sensor should fluctuate between 0.1V and 0.9V.
  3. If the readings are outside this range, replace the faulty oxygen sensor(s) with OEM or high-quality aftermarket parts, ensuring proper torque for the sensor installation (typically 30 Nm).

4. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. If all other components are functional, and the P0420 code persists, remove the catalytic converter.
  2. Inspect for signs of clogging or damage; a clogged converter may require replacement.
  3. Install a new catalytic converter, ensuring to use the appropriate gaskets and bolts, and torque to specifications (typically 40-50 Nm).

5. Clear Codes and Test

• Sub-steps:
  1. Use the OBD-II scanner to clear the P0420 code from the vehicle’s memory.
  2. Take the vehicle for a test drive to monitor performance and check if the check engine light returns.