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

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

Honda Pilot Third Generation (2016-present)

Severity: highDifficulty: mediumError Code: P04202-4 hours
3 min read
498 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 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 engine to cool before working on the exhaust system.

Symptoms

  • •Check engine light illuminated
  • •Decreased engine performance
  • •Poor fuel economy
  • •Failed emissions test
  • •Unusual smells from the exhaust

Diagnostic Steps

  1. 1Scan for error codes using an OBD-II scanner to confirm the P0420 code.
  2. 2Inspect the exhaust system visually for any signs of leaks or damage.
  3. 3Check the oxygen sensors' operation using a multimeter or OBD-II scanner.
  4. 4Measure the temperature difference between the upstream and downstream oxygen sensors.
  5. 5Inspect for any vacuum leaks that could affect the air-fuel mixture.
  6. 6Review maintenance records for any recent repairs or component replacements.

Solution

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.

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
  • Socket set
  • Torque wrench
  • Multimeter
  • Jack and jack stands

Parts Required

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

Additional Information

Error CodeP0420
Component

Exhaust System

Repair Time

2-4 hours

Difficulty

medium

Severity

high

Tools

5 items

Parts

3 items

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