FAULTBASE
NEWSASKCars
© 2025 FAULTBASE
All rights reserved.
v2.0.0 • Production
ContactPrivacyImpressum
Home/Cars/Honda/Civic/10th Generation (2016-2021)/why does my Honda Civic 10th Generation (2016-2021) check engine light keep coming on

why does my Honda Civic 10th Generation (2016-2021) check engine light keep coming on

Honda Civic 10th Generation (2016-2021)

Severity: mediumDifficulty: mediumError Code: P04201-3 hours
3 min read
500 words

Problem Statement

Learn how to diagnose and fix the check engine light issue in Honda Civic 10th Generation (2016-2021). Step-by-step guide with diagnostic procedures and repair instructions.

Error Code
P0420
Component
Engine
Repair Time
1-3 hours

Safety Warnings

  • ⚠Disconnect battery before working on electrical systems.
  • ⚠Allow engine to cool before opening any components.

Symptoms

  • •Check engine light illuminated
  • •Decreased engine performance or power
  • •Poor fuel economy
  • •Rough idle or engine stalling
  • •Increased exhaust emissions
  • •Unusual engine noises

Diagnostic Steps

  1. 1Scan for error codes using an OBD-II scanner to identify specific trouble codes.
  2. 2Inspect the gas cap for proper sealing and any signs of damage.
  3. 3Check engine oil and coolant levels, ensuring they are within normal ranges.
  4. 4Examine the air filter for clogs or excessive dirt.
  5. 5Inspect ignition components such as spark plugs and ignition coils for wear or damage.
  6. 6Test the fuel system for pressure and leaks, including the fuel injectors.

Solution

Solution

1. Preparation

  • Tools Required: OBD-II scanner, socket set, multimeter, torque wrench, fuel pressure gauge.
  • Ensure the vehicle is parked on a level surface and the engine is cool.
  • Disconnect the battery to ensure safety during repairs.

2. Addressing Error Codes

  • Use the OBD-II scanner to read the error codes.
  • For codes related to specific components (e.g., P0420 for catalytic converter efficiency), research further to determine the appropriate repair steps.

3. Inspecting and Replacing Components

  • Gas Cap: If the code indicates a loose or faulty gas cap, replace it with a new one, ensuring it clicks securely.
  • Spark Plugs: Remove the ignition coils and inspect the spark plugs. Replace if fouled or worn, using OEM specifications for gap settings.
  • Air Filter: Remove the airbox cover and inspect the air filter. Replace if dirty or clogged.
  • Fuel System Inspection:
    • Connect the fuel pressure gauge to the fuel rail and check the pressure against manufacturer specifications.
    • If low, check the fuel pump and filter for clogs or failures.

4. Reassemble and Clear Codes

  • Reassemble any components removed during inspection or replacement.
  • Reconnect the battery and use the OBD-II scanner to clear any codes.

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
  • Multimeter
  • Torque wrench
  • Fuel pressure gauge

Parts Required

  • Gas cap (if faulty)
  • Spark plugs (if worn)
  • Air filter (if dirty)
  • Fuel filter (if necessary)

Additional Information

Error CodeP0420
Component

Engine

Repair Time

1-3 hours

Difficulty

medium

Severity

medium

Tools

5 items

Parts

4 items

Related Faults

Discover similar issues

  1. why does my Honda Civic feel like it's losing acceleration power

    Learn how to diagnose and fix loss of acceleration power in Honda Civic. Step-by-step guide with diagnostic procedures and repair instructions.

    Component:Engine
    Symptoms
    • •Check engine light illuminated
    • •Reduced engine power during acceleration
    • +{count} more

  2. why is my Honda Civic making a whining noise when I turn the wheel

    Learn how to diagnose and fix whining noise when turning the steering wheel in Honda Civic. Step-by-step guide with diagnostic procedures and repair i...

    Component:Steering
    Symptoms
    • •Whining noise when turning the steering wheel
    • •Difficulty steering or increased effort required
    • +{count} more

  3. my Honda Civic won't start and just clicks what should I do

    Learn how to diagnose and fix a Honda Civic that won't start and just clicks. Step-by-step guide with diagnostic procedures and repair instructions.

    Component:Electrical
    Symptoms
    • •Single clicking sound when turning the key
    • •No engine crank or turnover
    • +{count} more

  4. why does my Honda Civic 10th Generation (2016-2021) make a loud whining noise

    Learn how to diagnose and fix a loud whining noise in Honda Civic 10th Generation (2016-2021). Step-by-step guide with diagnostic procedures and repai...

    Component:Steering
    Symptoms
    • •Loud whining noise, especially during acceleration
    • •Noise changes with engine RPM
    • +{count} more

  5. how to reset maintenance light on Honda Civic 10th Generation (2016-2021)

    Learn how to reset the maintenance light on your Honda Civic 10th Generation (2016-2021) with this step-by-step guide. Quick and easy instructions inc...

    Component:Electrical
    Symptoms
    • •Maintenance light illuminated on the dashboard
    • •Possible message display on the instrument cluster indicating maintenance required
    • +{count} more

  6. my Honda Civic has poor acceleration what could be causing it

    Discover how to diagnose and fix poor acceleration issues in Honda Civic. Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

    Component:Engine
    Symptoms
    • •Check engine light illuminated
    • •Engine stalling during acceleration
    • +{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