my Honda Pilot has a check engine light and code P0420, what does it mean?

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 prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Disconnect the wiring harness from each oxygen sensor.
3. Use a socket wrench to remove the sensors from the exhaust system.
4. Install new oxygen sensors by threading them into place and tightening them to manufacturer specifications (usually 30-40 lb-ft).
5. Reconnect the wiring harness to each sensor.

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

1. Remove the exhaust pipe connected to the catalytic converter by loosening the bolts using a socket set.
2. Carefully detach the catalytic converter from the exhaust system.
3. Inspect the catalytic converter for signs of damage or blockage.
4. If faulty, install a new catalytic converter, ensuring proper alignment with exhaust pipes.
5. Tighten bolts to manufacturer torque specifications.

4. Clear Codes and Test Drive

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the P0420 trouble code.
3. Start the engine and allow it to reach operating temperature.
4. Take the vehicle for a test drive to ensure the check engine light does not reappear.