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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor (pre-catalytic converter) using an O2 sensor socket.
  • Sub-steps:
    1. Locate the upstream O2 sensor in the exhaust manifold or downpipe.
    2. Disconnect the wiring harness from the sensor.
    3. Use the O2 sensor socket to unscrew the sensor from its mount.
• Install a new upstream oxygen sensor.
  • Torque specification: Tighten to manufacturer’s specified torque (usually around 30 lb-ft).
• Repeat the process for the downstream oxygen sensor if it shows signs of failure.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, cutting tool (if necessary), exhaust pipe clamps.
• Inspect the catalytic converter for any signs of physical damage or blockage.
• If replacement is necessary:
  • Remove the exhaust pipe connected to the catalytic converter.
  • Unbolt the catalytic converter from its mounts.
  • Install the new catalytic converter, ensuring proper alignment and sealing.
  • Reconnect the exhaust pipe and secure with clamps or bolts as required.

4. Clear Codes and Test

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code and any other related codes.
• Start the engine and allow it to reach operating temperature.
• Perform a test drive to monitor vehicle performance and check if the check engine light reappears.