my Honda Pilot YF3 (2016-2022) has a check engine light and code P0420, what should I do?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety during repairs.
• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, jack, jack stands.

2. Inspect and Replace Oxygen Sensors

• Sub-step 1: Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Sub-step 2: Use a wrench to carefully disconnect the electrical connectors from both oxygen sensors.
• Sub-step 3: Remove the oxygen sensors using the appropriate socket.
• Sub-step 4: Install new sensors by reversing the removal steps, ensuring the threads are clean and properly torqued to manufacturer's specifications (typically around 30-40 lb-ft).

3. Inspect and Replace Catalytic Converter

• Sub-step 1: Raise the vehicle using a jack and secure it with jack stands.
• Sub-step 2: Locate the catalytic converter in the exhaust system.
• Sub-step 3: Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe using a socket set.
• Sub-step 4: Inspect the catalytic converter for any signs of damage or clogging; if damaged, replace it with a new unit.
• Sub-step 5: Install the new catalytic converter and torque the bolts to the manufacturer's specifications.
• Sub-step 6: Reconnect any exhaust components that were removed.

4. Clear Codes and Test Drive

• Sub-step 1: Reconnect the vehicle's battery.
• Sub-step 2: Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
• Sub-step 3: Perform a test drive to ensure that the check engine light does not re-illuminate.