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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface with the engine off and cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter, socket set
• Remove the upstream (pre-catalytic) oxygen sensor using a socket wrench.
• Use a multimeter to test the voltage output of the sensor (should fluctuate between 0.1V and 0.9V).
• If the sensor is faulty, replace it.

3. Check Catalytic Converter

• Tools Required: Backpressure gauge
• Remove the downstream (post-catalytic) oxygen sensor.
• Insert the backpressure gauge into the O2 sensor port.
• Start the engine and check for backpressure; it should be below 2.5 psi at 2,500 RPM.
• If backpressure exceeds specifications, replace the catalytic converter.

4. Repair Exhaust Leaks

• Tools Required: Exhaust sealant or new clamps
• Inspect the exhaust system for leaks.
• If leaks are found, repair them using exhaust sealant or replace damaged sections.
• Tighten any loose clamps or connections.

5. Clear Codes and Test Drive

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Test drive the vehicle for at least 20 minutes to ensure the issue does not return.