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Home/Cars/Honda/Pilot/YF3 (2016-2022)/how to fix P0420 code on Honda Pilot Third Generation (2016-present)

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

Honda Pilot YF3 (2016-2022)

Severity: highDifficulty: mediumError Code: P04202-4 hours
3 min read
566 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix P0420 code in Honda Pilot (2016-present). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Error Code
P0420
Component
Exhaust System
Repair Time
2-4 hours

Safety Warnings

  • ⚠Disconnect the battery before working on electrical systems.
  • ⚠Allow the exhaust system to cool before inspection or repair.

Symptoms

  • •Check engine light illuminated
  • •Decreased fuel efficiency
  • •Rough idle or engine stalling
  • •Increased emissions
  • •Failure in emissions testing

Diagnostic Steps

  1. 1Scan the vehicle's computer using an OBD-II scanner to confirm the P0420 code.
  2. 2Inspect the exhaust system for visible damage or leaks.
  3. 3Check the oxygen sensors (upstream and downstream) for proper operation and wiring integrity.
  4. 4Test the catalytic converter for proper temperature differential across it (inlet vs. outlet).
  5. 5Inspect the engine for vacuum leaks that could affect the air-fuel ratio.
  6. 6Review the vehicle’s maintenance history for recent repairs or changes that may impact emissions.

Solution

Solution

1. Preparation

  • Gather necessary tools and parts.
  • Disconnect the battery to ensure safety while working on the vehicle.

2. Inspect and Replace Oxygen Sensors

  • Tools Required: O2 sensor socket, torque wrench, penetrating oil.
  • Sub-steps:
    1. Locate the upstream and downstream oxygen sensors on the exhaust system.
    2. Use penetrating oil to loosen the sensors. Allow it to soak for a few minutes.
    3. Disconnect the electrical connectors from both oxygen sensors.
    4. Remove the sensors using the O2 sensor socket.
    5. Install new sensors, ensuring they are torqued to the manufacturer's specifications (typically around 30 lb-ft).
    6. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

  • Tools Required: Socket set, jack and jack stands, exhaust sealant.
  • Sub-steps:
    1. Raise the vehicle securely on jack stands and remove any protective covers if necessary.
    2. Examine the catalytic converter for damage or blockages.
    3. If replacement is needed, unbolt the catalytic converter from the exhaust pipes and oxygen sensors.
    4. Install the new catalytic converter, ensuring all bolts are tightened to the specified torque (check manufacturer specs).
    5. Apply exhaust sealant to the joints if recommended by the manufacturer.

4. Clear Codes and Test Drive

  • Tools Required: OBD-II scanner.
  • Sub-steps:
    1. Reconnect the battery.
    2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
    3. Start the engine and allow it to reach operating temperature.
    4. Take the vehicle for a test drive to ensure no new codes appear and that the symptoms are resolved.

Verification

After completing the repair, verify that the issue has been resolved:

  • Test the affected component to ensure it functions correctly
  • Check for any error codes or warning lights
  • Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

  • OBD-II scanner
  • O2 sensor socket
  • Torque wrench
  • Socket set
  • Jack and jack stands
  • Penetrating oil
  • Exhaust sealant

Parts Required

  • Upstream oxygen sensor
  • Downstream oxygen sensor
  • Catalytic converter (if necessary)

Additional Information

Error CodeP0420
Component

Exhaust System

Repair Time

2-4 hours

Difficulty

medium

Severity

high

Tools

7 items

Parts

3 items

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