FAULTBASE
NEWSASKCars
© 2025 FAULTBASE
All rights reserved.
v2.0.0 • Production
ContactPrivacyImpressum
Home/Cars/Honda/CR-V/6th Gen (2023-Present)/how to fix P0420 code in Honda CR-V Fifth Generation (2017-2022)

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

Honda CR-V 6th Gen (2023-Present)

Severity: highDifficulty: mediumError Code: P04202-4 hours
3 min read
460 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 CR-V (2017-2022). 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
  • •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 is present.
  2. 2Inspect the exhaust system for any visible leaks or damage.
  3. 3Check the upstream and downstream oxygen sensors for proper operation.
  4. 4Test the catalytic converter temperature with a thermometer to compare inlet and outlet temperatures.
  5. 5Inspect the air-fuel mixture to ensure it is within specifications.
  6. 6Check for any exhaust blockages or restrictions.

Solution

Solution

1. Preparation

  • Gather necessary tools and parts.
  • Ensure the vehicle is parked on a flat surface and the engine is off.
  • Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

  • Sub-steps:
    1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
    2. Unplug the electrical connectors from both sensors.
    3. Use an O2 sensor socket to remove the sensors from the exhaust pipe.
    4. Install new oxygen sensors and torque them to manufacturer's specifications (typically around 30 lb-ft).
    5. Reconnect the electrical connectors.

3. Check and Replace the Catalytic Converter

  • Sub-steps:
    1. Inspect the catalytic converter for physical damage or blockage.
    2. If damaged, unbolt the catalytic converter from the exhaust system.
    3. Install a new catalytic converter, ensuring all gaskets and seals are replaced.
    4. Torque the bolts to the manufacturer's specifications (typically around 40 lb-ft).
    5. Reconnect any exhaust hangers or brackets.

4. Clear the Codes

  • Sub-steps:
    1. Reconnect the battery.
    2. Use an OBD-II scanner to clear the P0420 code from the ECM.
    3. Start the engine and allow it to reach operating temperature.

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
  • Torque wrench
  • Socket set
  • Safety glasses

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 Sixth Generation (2023-present) have poor acceleration

    Learn how to diagnose and fix poor acceleration in the 2023 Honda CR-V. Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

    Component:Engine
    Symptoms
    • •Check engine light illuminated
    • •Engine hesitates or stutters during acceleration
    • +{count} more
  2. how to check for a blown fuse in Honda CR-V Fifth Generation (2017-2022)

    Learn how to check for a blown fuse in Honda CR-V Fifth Generation (2017-2022). Step-by-step guide with diagnostic procedures and repair instructions.

    Component:Electrical
    Symptoms
    • •Inoperative electrical component (e.g., lights, radio, power windows)
    • •Warning lights illuminated on the dashboard
    • +{count} more
  3. why does my Honda CR-V Sixth Generation (2023-present) battery die overnight after being parked

    Discover how to diagnose and fix battery drain issues in Honda CR-V Sixth Generation. Step-by-step guide with symptoms, diagnostic steps, and repair i...

    Component:Electrical
    Symptoms
    • •Battery warning light illuminated on the dashboard
    • •Difficulty starting the engine in the morning
    • +{count} more
  4. how to troubleshoot Honda CR-V Sixth Generation (2023-present) ABS light on

    Learn how to troubleshoot and fix the ABS light on a 2023 Honda CR-V. Step-by-step guide with diagnostic procedures and repair instructions.

    Component:Brakes
    Symptoms
    • •ABS light illuminated on the dashboard
    • •Reduced braking efficiency or performance
    • +{count} more
  5. why does my Honda CR-V Sixth Generation (2023-present) battery die overnight when parked

    Learn how to diagnose and fix battery drain issues in Honda CR-V Sixth Generation. Step-by-step guide with symptoms, diagnostic steps, and solutions.

    Component:Electrical
    Symptoms
    • •Battery warning light illuminated on the dashboard
    • •Difficulty starting the engine after being parked overnight
    • +{count} more
  6. my Honda CR-V's coolant is leaking, what should I do?

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

    Component:Cooling System
    Symptoms
    • •Visible coolant puddles under the vehicle
    • •Sweet smell of coolant inside or around the engine bay
    • +{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