how to diagnose Ford Explorer Sixth Generation (2020-present) P0420 code

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, exhaust thermometer, socket set, jack and jack stands.
• Safety Warnings: Disconnect the battery before starting work on electrical systems and allow the engine to cool before working on the exhaust system.

2. Address Exhaust Leaks

• Sub-step 1: Lift the vehicle and securely support it with jack stands.
• Sub-step 2: Inspect the exhaust system for any visible leaks or damage.
• Sub-step 3: Repair or replace any damaged exhaust components as necessary (e.g., gaskets, pipes, mufflers).

3. Replace Oxygen Sensors (if necessary)

• Sub-step 1: Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Sub-step 2: Disconnect the wiring harness from the sensors.
• Sub-step 3: Remove the sensors using a socket or wrench.
• Sub-step 4: Install new oxygen sensors, ensuring they are tightened to the manufacturer’s specifications (usually around 30 lb-ft).
• Sub-step 5: Reconnect the wiring harness.

4. Replace Catalytic Converter (if necessary)

• Sub-step 1: Remove any brackets or heat shields securing the catalytic converter.
• Sub-step 2: Unbolt the catalytic converter from the exhaust system using a socket set.
• Sub-step 3: Install the new catalytic converter and secure it with bolts, tightening to the manufacturer's specifications (typically around 40-50 lb-ft).
• Sub-step 4: Reinstall any heat shields or brackets removed during the process.

5. Clear Codes and Test Drive

• Sub-step 1: Reconnect the battery and use the OBD-II scanner to clear the P0420 code.
• Sub-step 2: Start the engine and let it idle for a few minutes.
• Sub-step 3: Take the vehicle for a test drive to ensure the issue has been resolved and monitor for any reoccurrence of the check engine light.