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Home/Cars/Honda/Pilot/Third Generation (2016-present)/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 Third Generation (2016-present)

Severity: mediumDifficulty: mediumError Code: P04202-4 hours
3 min read
582 words

Problem Statement

Learn how to diagnose and fix P0420 exhaust system issue in Honda Pilot. Step-by-step guide with diagnostic procedures 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 attempting repairs.

Symptoms

  • •Check engine light illuminated
  • •Poor fuel economy
  • •Loss of power during acceleration
  • •Increased emissions
  • •Rattling noise from the exhaust system

Diagnostic Steps

  1. 1Scan for error codes using an OBD-II scanner to confirm P0420 and check for any other related codes.
  2. 2Inspect the exhaust system for visible leaks or damage, especially around the catalytic converter.
  3. 3Check the operation of the upstream and downstream oxygen sensors using a multimeter or scan tool.
  4. 4Measure the temperature difference between the upstream and downstream oxygen sensor to assess catalytic converter efficiency.
  5. 5Inspect for any exhaust blockages or restrictions, including mufflers and resonators.
  6. 6Review the vehicle's maintenance history for recent repairs or changes that could affect the exhaust system.

Solution

Solution

1. Preparation

  • Gather tools and parts needed for the repair.
  • Disconnect the vehicle battery to ensure safety.

Tools Required:

  • OBD-II scanner
  • Multimeter
  • Socket set
  • Torque wrench
  • Safety goggles
  • Gloves

2. Inspect and Replace Oxygen Sensors

  1. Locate the oxygen sensors: The upstream sensor is before the catalytic converter, and the downstream sensor is after it.
  2. Unplug the electrical connectors from both sensors.
  3. Remove the sensors: Use a socket wrench to carefully unscrew the sensors from their mounts.
  4. Install new oxygen sensors: Apply anti-seize compound to the threads of the new sensors and install them, tightening to the manufacturer's specifications (usually around 30 ft-lbs).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

  1. Remove the exhaust heat shield: Unscrew any bolts holding the shield in place and set it aside.
  2. Unbolt the catalytic converter: Use a socket wrench to remove the bolts connecting the converter to the exhaust pipe and engine manifold.
  3. Inspect the old catalytic converter: Check for physical damage or excessive carbon buildup.
  4. Install the new catalytic converter: Position it in place and secure it with bolts, tightening to the specified torque settings.
  5. Reattach the exhaust heat shield.

4. Reset the Check Engine Light

  1. Reconnect the battery.
  2. Use an OBD-II scanner to clear the P0420 code from the ECM.
  3. Take the vehicle for a test drive to ensure that the check engine light does not reappear.

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
  • Multimeter
  • Socket set
  • Torque wrench
  • Safety goggles
  • Gloves

Parts Required

  • Upstream oxygen sensor
  • Downstream oxygen sensor
  • Catalytic converter

Additional Information

Error CodeP0420
Component

Exhaust System

Repair Time

2-4 hours

Difficulty

medium

Severity

medium

Tools

6 items

Parts

3 items

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