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 and engaged in park.
• Disconnect the battery to avoid electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Using the O2 sensor socket, remove the upstream oxygen sensor (pre-catalytic converter).
• Inspect the sensor for any signs of damage or contamination.
• If found defective, replace with a new OEM or high-quality aftermarket sensor.
• Repeat the process for the downstream oxygen sensor (post-catalytic converter).
• Torque the new sensors to manufacturer specifications (usually around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, wrench set, exhaust pipe cutter (if necessary), jack stands.
• Raise the vehicle securely using jack stands.
• Disconnect the exhaust pipes from the catalytic converter by loosening the clamps or bolts.
• Remove the catalytic converter from its mounting points.
• Inspect for blockages, and if damaged or clogged, replace it with a new catalytic converter that meets OEM specifications.
• Reinstall the new catalytic converter, ensuring proper alignment, and tighten all connections to manufacturer torque specifications.

4. Clear Codes and Test Drive

• Reconnect the battery and use an OBD-II scanner to clear any stored codes.
• Start the engine and let it idle for a few minutes.
• Take the vehicle for a test drive under varied conditions (highway and city driving) to ensure the check engine light does not reappear.