my Ford Explorer Sixth Generation (2020-present) shows a check engine light and P0420 code, what doe...

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle battery to ensure safety while working on electrical components.
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench, multimeter
• Remove the upstream and downstream oxygen sensors:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Use an O2 sensor socket and ratchet to carefully unscrew the sensors from their respective locations.
• Test the sensors with a multimeter:
  1. Set the multimeter to the voltage setting.
  2. Start the engine and monitor the voltage output of each sensor.
  3. If the upstream sensor doesn’t fluctuate between 0.1V to 0.9V or the downstream sensor is stagnant, replace the faulty sensor.
• Install the new sensors:
  1. Apply anti-seize compound to the threads of the new sensors.
  2. Screw the sensors back into place and torque to the manufacturer’s specifications (typically around 30 ft-lbs).

3. Check and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, torque wrench
• Inspect the catalytic converter:
  1. If the oxygen sensors are functioning correctly, inspect the catalytic converter for significant damage or clogging.
  2. Shake the catalytic converter gently; if it rattles, it may be damaged internally.
• Remove the catalytic converter:
  1. Raise the vehicle securely on jack stands.
  2. Disconnect the exhaust pipe and any hangers.
  3. Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
• Install a new catalytic converter:
  1. Position the new catalytic converter in place.
  2. Bolt it securely to the exhaust manifold and exhaust pipe, tightening to manufacturer’s torque specifications.