my Honda Pilot YF4 (2023-Present) has a check engine light with code P0420, what to do?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on the electrical system.
• Allow the engine to cool down before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Sub-step 1: Locate the upstream and downstream oxygen sensors (usually near the exhaust manifold and after the catalytic converter).
• Sub-step 2: Unplug the electrical connectors from both sensors.
• Sub-step 3: Use an oxygen sensor socket to remove the sensors.
• Sub-step 4: Install new oxygen sensors and torque them to the manufacturer's specifications (typically 30-40 lb-ft).
• Sub-step 5: Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-step 1: Remove the exhaust components connected to the catalytic converter using a socket set.
• Sub-step 2: Carefully detach the catalytic converter from the exhaust system.
• Sub-step 3: Inspect the new catalytic converter for any damage.
• Sub-step 4: Install the new catalytic converter, ensuring proper alignment.
• Sub-step 5: Torque all connections to the manufacturer's specifications (typically around 25-30 lb-ft for exhaust bolts).

4. Reconnect Battery and Clear Codes

• Sub-step 1: Reconnect the battery terminals.
• Sub-step 2: Use the OBD-II scanner to clear any stored codes.
• Sub-step 3: Take the vehicle for a test drive to ensure the check engine light does not reappear.