how to fix Ford Explorer Fifth Generation (2011-2019) check engine light P0420 code

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, jack and jack stands, safety goggles, gloves.
• Clear any stored codes in the vehicle's computer and take the vehicle for a test drive to confirm the P0420 code returns.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Disconnect the battery: Disconnect the negative terminal to ensure safety while working with electrical components.
3. Remove the upstream oxygen sensor:
   • Use a socket wrench to unscrew the sensor from the exhaust manifold.
   • Disconnect the electrical connector.
4. Install the new upstream oxygen sensor:
   • Apply anti-seize compound to the threads of the new sensor.
   • Screw it into place and tighten to the manufacturer’s specifications (typically around 30 lb-ft).
   • Reconnect the electrical connector.
5. Repeat for the downstream oxygen sensor: Follow the same steps to remove and replace the downstream sensor.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Check for blockage: If the catalytic converter is damaged or blocked, it needs to be replaced.
2. Raise the vehicle: Use a jack and jack stands to safely lift the vehicle.
3. Remove the catalytic converter:
   • Disconnect the exhaust pipes at both ends of the catalytic converter using a socket set.
   • Remove any mounting brackets or hangers.
4. Install the new catalytic converter:
   • Position the new catalytic converter and connect it to the exhaust pipes.
   • Secure all bolts and brackets to the manufacturer’s torque specifications.
5. Reconnect the battery: Reattach the negative terminal of the battery.