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how to fix P0420 code on Honda Accord 9th Generation (2013-2017) - Honda Accord
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how to fix P0420 code on Honda Accord 9th Generation (2013-2017)

Honda Accord 9th Generation (2013-2017)

Error Codes
2-4 hours
Time
medium
Difficulty
high
Severity
Error Code: P0420
Navigation
ProblemSymptomsDiagnosisSolution
ProblemSymptomsDiagnosisSolution
3 min read
550 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 Accord (2013-2017). Step-by-step guide with diagnostic procedures and repair instructions.

Error Code
P0420
Affected Component
Exhaust System
Estimated Time
2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

  • •Disconnect battery before working on electrical systems.
  • •Allow the exhaust system to cool before inspecting or working on it to avoid burns.

Symptoms

  • •Check engine light illuminated
  • •Decreased fuel efficiency
  • •Poor acceleration or loss of power
  • •Unusual exhaust odor
  • •Failed emissions test

Diagnostic Steps

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

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
  • •Oxygen sensor socket
  • •Socket set
  • •Ratchet wrench
  • •Torque wrench
  • •Breaker bar

Parts Required

  • •Oxygen sensor (upstream and/or downstream as needed)
  • •Catalytic converter (if necessary)
  • •Exhaust gaskets

Additional Information

Error Code
P0420
Affected Component
Exhaust System
Estimated Time
2-4 hours
Difficulty
medium
Severity
high
Tools Required
6 items
Parts Required
3 items

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Solution
1. Preparation
  • Gather tools and parts needed for the repair.
  • Disconnect the battery to ensure safety during repairs.
  • Raise the vehicle and secure it on jack stands.
2. Inspect and Replace Oxygen Sensors

  1. Locate the Oxygen Sensors

    • The upstream (pre-catalytic) sensor is before the catalytic converter, and the downstream (post-catalytic) sensor is after it.

  2. Remove Oxygen Sensor

    • Use an oxygen sensor socket to carefully unscrew the sensor from the exhaust pipe.
    • Tools Required: Oxygen sensor socket, ratchet wrench.

  3. Install New Oxygen Sensor

    • Apply anti-seize compound on the threads of the new oxygen sensor.
    • Install the new sensor and torque it to the manufacturer’s specifications (usually around 30-35 ft-lbs).
3. Inspect and Replace Catalytic Converter (if necessary)

  1. Inspect Catalytic Converter

    • Check for physical damage, rattling, or discoloration that indicates overheating.

  2. Remove Catalytic Converter

    • Disconnect any exhaust hangers and remove the bolts securing the catalytic converter to the exhaust system.
    • Tools Required: Socket set, breaker bar for stubborn bolts.

  3. Install New Catalytic Converter

    • Position the new catalytic converter and secure it with bolts, ensuring all gaskets are in place.
    • Torque bolts to the manufacturer’s specifications (usually around 25-30 ft-lbs).
4. Reset the Check Engine Light
  • Reconnect the battery and use an OBD-II scanner to erase the P0420 code from the ECU.
5. Test Drive the Vehicle
  • Take the vehicle for a test drive to ensure that the check engine light does not reappear and the vehicle operates smoothly.