my Ford Explorer has a check engine light with code P0420 what should I do

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the vehicle to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Find the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Remove sensors: Use an oxygen sensor socket to carefully remove both sensors. Take note of their positions.
3. Inspect the sensors: Check for signs of wear or damage. If they appear faulty, replace them with new ones.
4. Install new sensors: Apply anti-seize compound on the threads of the new sensors, then install them and torque to manufacturer specifications (usually around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter (if necessary)

1. Inspect the catalytic converter: Check for physical damage or clogs.
2. Remove the catalytic converter: Use a socket set to unbolt the catalytic converter from the exhaust system. Be cautious of exhaust hangers and any remaining gaskets.
3. Install the new catalytic converter: Position the new catalytic converter in place, ensuring that the gaskets are properly seated. Torque the bolts to manufacturer specifications.
4. Reconnect exhaust components: Reattach any exhaust hangers and check for tightness.

4. Clear Error Codes

1. Reconnect the negative battery terminal.
2. Use an OBD-II scanner to clear the P0420 code from the vehicle’s computer.
3. Start the engine and allow it to reach operating temperature.