how to fix P0420 code in Honda Pilot Third Generation (2016-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the battery to prevent any electrical shorts during repairs.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: The upstream sensor is typically located before the catalytic converter, while the downstream sensor is after it.
2. Remove the sensors: Use an oxygen sensor socket to carefully unscrew each sensor.
3. Test the sensors: Using a multimeter, check the voltage output of each sensor to ensure they are functioning correctly. Replace any faulty sensors.
4. Install new sensors: Apply anti-seize compound to the threads of the new sensors and install them securely, ensuring they are tightened to manufacturer specifications (usually around 30-40 ft-lbs).

3. Inspect and Replace the Catalytic Converter

1. Remove the catalytic converter: Unbolt the exhaust flanges securing the catalytic converter to the exhaust system, and remove any hangers.
2. Inspect the catalyst: Check for physical damage or excessive soot buildup. If damaged, proceed with replacement.
3. Install the new catalytic converter: Position the new converter in place, and secure it with bolts to the exhaust flanges. Use a torque wrench to tighten to manufacturer specifications.
4. Reconnect exhaust hangers to ensure proper fitment and alignment.

4. Reconnect Battery and Clear Codes

1. Reconnect the battery: Reattach the negative terminal and ensure it is secure.
2. Clear the error codes: Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
3. Test drive the vehicle: Drive the vehicle for at least 20-30 minutes to allow the system to recalibrate and check for any reoccurring codes.