FAULTBASE
NEWSASKCars
© 2025 FAULTBASE
All rights reserved.
v2.0.0 • Production
ContactPrivacyImpressum
Home/Cars/Tesla/Model 3/Highland (2024-present)/how to fix P0420 code in Tesla Model 3 Highland (2024-present)?

how to fix P0420 code in Tesla Model 3 Highland (2024-present)?

Tesla Model 3 Highland (2024-present)

Severity: mediumDifficulty: mediumError Code: P04202-4 hours
3 min read
588 words

Problem Statement

Learn how to diagnose and fix P0420 exhaust system issue in Tesla Model 3 Highland. Step-by-step guide with diagnostic procedures and repair instructions.

Error Code
P0420
Component
Exhaust System
Repair Time
2-4 hours

Safety Warnings

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

Symptoms

  • •Check engine light illuminated
  • •Decreased fuel efficiency
  • •Poor acceleration
  • •Increased exhaust emissions
  • •Unusual exhaust smells (e.g., sulfur or rotten egg odor)

Diagnostic Steps

  1. 1Scan the vehicle's OBD-II system for error codes to confirm P0420 and check for any other related codes.
  2. 2Inspect the exhaust system visually for any visible cracks, leaks, or damage to the catalytic converter.
  3. 3Check the oxygen sensors before and after the catalytic converter for proper operation using a multimeter.
  4. 4Measure exhaust back pressure to ensure there are no blockages in the system.
  5. 5Verify that the engine is running at the correct operating temperature and that the coolant and oil are at proper levels.

Solution

Solution

1. Preparation

  • Gather tools and parts.
  • Ensure the vehicle is parked on a flat surface and the engine is cool.
  • Disconnect the negative battery terminal to prevent electrical issues.

2. Inspect and Replace Oxygen Sensors

  1. Locate Oxygen Sensors: Identify the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect Electrical Connectors: Carefully unplug the electrical connectors from both oxygen sensors.
  3. Remove Sensors: Use an O2 sensor socket to unscrew and remove both sensors from the exhaust system.
  4. Install New Sensors: Apply anti-seize compound to the threads of the new sensors, then install and torque them to the manufacturer's specifications (usually around 30 ft-lbs).
  5. Reconnect Electrical Connectors: Plug the connectors back into the new sensors.

3. Inspect and Replace the Catalytic Converter (if necessary)

  1. Remove Exhaust Components: If the catalytic converter is suspected to be faulty, disconnect the exhaust pipe and any brackets securing the catalytic converter using a socket set.
  2. Remove Catalytic Converter: Carefully take the catalytic converter out, ensuring no damage to surrounding components.
  3. Install New Catalytic Converter: Place the new catalytic converter in position, using new gaskets as needed, and secure it with bolts to the exhaust system.
  4. Reattach Exhaust Components: Reconnect all parts of the exhaust system securely.

4. Reset the OBD-II System

  1. Reconnect Battery: Reconnect the negative battery terminal.
  2. Use OBD-II Scanner: Clear the error codes using an OBD-II scanner and reset the check engine light.

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
  • O2 sensor socket
  • Torque wrench
  • Anti-seize compound
  • Multimeter

Parts Required

  • Upstream oxygen sensor
  • Downstream oxygen sensor
  • Catalytic converter (if found faulty)
  • Exhaust gaskets (if needed)

Additional Information

Error CodeP0420
Component

Exhaust System

Repair Time

2-4 hours

Difficulty

medium

Severity

medium

Tools

6 items

Parts

4 items

Related Faults

Discover similar issues

  1. why is my Tesla Model 3 Highland (2024-present) making a clunking noise when going over bumps?

    Learn how to diagnose and fix clunking noise in Tesla Model 3 Highland suspension. Step-by-step guide with diagnostic procedures and repair instructio...

    Component:Suspension
    Symptoms
    • •Clunking noise when going over bumps or uneven surfaces
    • •Possible rattling sounds during normal driving
    • +{count} more
  2. why do I hear a whistling noise from my Tesla Model 3 Highland (2024-present)

    Learn how to diagnose and fix the whistling noise in your 2024 Tesla Model 3 Highland. Step-by-step guide with diagnostic procedures and repair instru...

    Component:Body/Interior
    Symptoms
    • •Whistling noise while driving
    • •Noise varies with vehicle speed
    • +{count} more
  3. how to troubleshoot power windows not working in my Tesla Model 3 Highland (2024-present)

    Learn how to troubleshoot and fix power windows not working in Tesla Model 3 Highland. Step-by-step guide with diagnostic procedures and repair instru...

    Component:Electrical
    Symptoms
    • •Power windows do not respond to switches
    • •Window control buttons do not light up
    • +{count} more
  4. why does my Tesla Model 3 Highland (2024-present) make a popping noise when turning?

    Learn how to diagnose and fix popping noise when turning in Tesla Model 3 Highland. Step-by-step guide with diagnostic procedures and repair instructi...

    Component:Suspension
    Symptoms
    • •Popping or clunking noise during turns
    • •Noise may increase with sharper turns
    • +{count} more
  5. how to fix C0020 error code in my Tesla Model 3 Highland (2024-present)

    C0020

    Learn how to diagnose and fix C0020 ABS issue in Tesla Model 3 Highland. Step-by-step guide with diagnostic procedures and repair instructions.

    Component:Brakes
    Symptoms
    • •ABS warning light illuminated on the dashboard
    • •Inconsistent braking performance
    • +{count} more
  6. why does my Tesla Model 3 Highland (2024-present) brake light stay on after parking

    Learn how to diagnose and fix the issue of the brake light staying on in Tesla Model 3 Highland. Step-by-step guide with diagnostic procedures and rep...

    Component:Brakes
    Symptoms
    • •Brake light remains on after the vehicle is parked.
    • •Possible alert displayed on the dashboard regarding brake system.
    • +{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