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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, jack and jack stands.
• Ensure the vehicle is parked on a level surface and the engine is cool. Disconnect the battery before starting repairs.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream (pre-catalytic) and downstream (post-catalytic) sensors.
2. Remove the upstream oxygen sensor:
   • Use a socket wrench to unscrew the sensor.
   • Disconnect the electrical connector.
3. Install the new upstream oxygen sensor:
   • Apply anti-seize compound to the threads of the new sensor.
   • Torque to manufacturer specifications (typically around 30 lb-ft).
4. Repeat for the downstream oxygen sensor, if necessary.

3. Check and Replace Catalytic Converter

1. Inspect the catalytic converter for physical damage or clogging.
2. Remove the catalytic converter:
   • Loosen the exhaust clamps and bolts.
   • Carefully detach the catalytic converter from the exhaust system.
3. Install the new catalytic converter:
   • Position the new converter and secure it with bolts and clamps.
   • Torque to manufacturer specifications (check model specs).
4. Reconnect the exhaust system ensuring there are no leaks.

4. Clear Error Codes

1. Reconnect the battery and start the engine.
2. Use the OBD-II scanner to clear the P0420 code from the ECM.