how to fix P0420 code on Ford Explorer Fifth Generation (2011-2019)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal.

2. Inspect and Replace Oxygen Sensors

• 2.1 Locate the pre-cat (upstream) and post-cat (downstream) oxygen sensors on the exhaust system.
• 2.2 Using a socket wrench, carefully remove both oxygen sensors.
• 2.3 Inspect the sensors for any signs of damage or contamination.
• 2.4 If faulty, install new oxygen sensors, ensuring they are properly tightened (generally to the manufacturer's specification, often around 30-40 ft-lbs).
• 2.5 Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

• 3.1 If the catalytic converter is determined to be faulty after testing, disconnect the exhaust pipes leading to and from the catalytic converter.
• 3.2 Remove any mounting bolts using a socket set, taking care to preserve any gaskets for reuse if they are in good condition.
• 3.3 Remove the old catalytic converter and install the new one, ensuring it fits securely and aligns correctly with the exhaust system.
• 3.4 Torque bolts to the manufacturer's specifications, typically around 30-40 ft-lbs.
• 3.5 Reinstall any gaskets or seals as needed and reconnect the exhaust pipes.

4. Reconnect Battery and Clear Codes

• 4.1 Reconnect the negative battery terminal.
• 4.2 Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
• 4.3 Start the engine and allow it to reach operating temperature.