FAULTBASE
NEWSASKCars
© 2025 FAULTBASE
All rights reserved.
v2.0.0 • Production
ContactPrivacyImpressum
Home/Cars/Honda/CR-V/Sixth Generation (2023-present)/how to fix Honda CR-V Fifth Generation (2017-2022) P0420 code

how to fix Honda CR-V Fifth Generation (2017-2022) P0420 code

Honda CR-V Sixth Generation (2023-present)

Severity: highDifficulty: mediumError Code: P04202-4 hours
3 min read
545 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 catalytic converter inefficiency in Honda CR-V (2017-2022). 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 engine to cool before handling exhaust components.

Symptoms

  • •Check engine light illuminated
  • •Decreased fuel efficiency
  • •Rough engine idle
  • •Failed emissions test
  • •Unusual exhaust noise
  • •Strong fuel odor

Diagnostic Steps

  1. 1Scan the vehicle’s OBD-II system for error codes to confirm P0420 and check for any additional codes.
  2. 2Inspect the exhaust system for visible leaks, particularly before and after the catalytic converter.
  3. 3Check the oxygen sensors using a multimeter to ensure they are functioning properly.
  4. 4Measure the temperature difference between the inlet and outlet of the catalytic converter using an infrared thermometer.
  5. 5Inspect for any engine performance issues, such as misfires or poor combustion.
  6. 6Verify that the air-fuel mixture is within the manufacturer's specifications.

Solution

Solution

1. Preparation

  • Gather tools and parts necessary for the repair.
  • Disconnect the vehicle's battery to prevent electrical shorts.
  • Safety goggles and gloves should be worn throughout the process.

2. Inspect and Replace Oxygen Sensors

  1. Locate the oxygen sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Remove the upstream sensor:
    • Use an O2 sensor socket and ratchet to unscrew the sensor.
    • Disconnect the electrical connector.
  3. Install the new upstream sensor:
    • Apply anti-seize compound to the threads.
    • Screw in the new sensor and connect the electrical harness.
  4. Repeat for the downstream sensor: Follow the same steps to replace the downstream O2 sensor if it was found to be defective.

3. Inspect and Replace the Catalytic Converter

  1. Check for blockages or damage: Inspect the catalytic converter for any signs of physical damage or clogging.
  2. Remove the catalytic converter:
    • Loosen and remove the bolts or clamps securing the catalytic converter to the exhaust system using a socket set.
    • Carefully take out the catalytic converter from the exhaust system.
  3. Install the new catalytic converter:
    • Position the new catalytic converter and secure it with bolts or clamps.
    • Ensure all connections are tight and there are no leaks.

4. Reset the Engine Control Module (ECM)

  1. Reconnect the battery: After completing the repairs, reconnect the battery terminals.
  2. Use an OBD-II scanner to clear the P0420 trouble 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
  • O2 sensor socket
  • Ratchet and socket set
  • Infrared thermometer
  • Torque wrench

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

high

Tools

5 items

Parts

3 items

Related Faults

Discover similar issues

  1. why does my Honda CR-V make a loud noise when I accelerate hard

    Learn how to diagnose and fix loud noise during hard acceleration in Honda CR-V. Step-by-step guide with diagnostic procedures and repair instructions...

    Component:Exhaust System
    Symptoms
    • •Loud noise during hard acceleration
    • •Possible vibration felt in the cabin
    • +{count} more
  2. why is my Honda CR-V using more fuel than usual

    Learn how to diagnose and fix increased fuel consumption in Honda CR-V. Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

    Component:Fuel System
    Symptoms
    • •Check engine light illuminated
    • •Rough idle
    • +{count} more
  3. how to diagnose Honda CR-V Sixth Generation (2023-present) overheating issues

    Learn how to diagnose and fix overheating issues in the Honda CR-V Sixth Generation (2023-present). Step-by-step guide with diagnostic procedures and ...

    Component:Cooling System
    Symptoms
    • •Engine temperature gauge reading higher than normal
    • •Steam or coolant leaks from the engine bay
    • +{count} more
  4. why does my Honda CR-V use so much gas lately

    Discover how to diagnose and resolve increased fuel consumption in Honda CR-V. Step-by-step guide with symptoms, diagnostic steps, and solutions.

    Component:Fuel System
    Symptoms
    • •Check engine light illuminated
    • •Rough idle or engine misfires
    • +{count} more
  5. how to fix carbon buildup in Honda CR-V Sixth Generation (2023-present)

    Learn how to diagnose and fix carbon buildup in Honda CR-V Sixth Generation (2023-present). Step-by-step guide with symptoms, diagnostic steps, and re...

    Component:Engine
    Symptoms
    • •Check engine light illuminated
    • •Rough idle or stalling
    • +{count} more
  6. how to address the transmission fluid leak in my Honda CR-V Sixth Generation (2023-present)

    Learn how to diagnose and repair transmission fluid leaks in Honda CR-V Sixth Generation. Step-by-step guide with symptoms, diagnostic steps, and solu...

    Component:Transmission
    Symptoms
    • •Transmission fluid puddles or spots under the vehicle
    • •Warning light illuminated on the dashboard (if equipped)
    • +{count} more

Share this solution

Comments

Sign in to share your thoughts

Sign In

No comments yet

Be the first to share your thoughts

Back to Generation