FAULTBASE
NEWSASKCars
© 2025 FAULTBASE
All rights reserved.
v2.0.0 • Production
ContactPrivacyImpressum
Home/Cars/Subaru/Outback/4th Generation (2010-2014)/how to fix P0420 code on Tesla Outback 4th Generation (2010-2014)

how to fix P0420 code on Tesla Outback 4th Generation (2010-2014)

Subaru Outback 4th Generation (2010-2014)

Severity: highDifficulty: mediumError Code: P04203-5 hours
3 min read
561 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 related to catalytic converter efficiency in Subaru Outback 2010-2014. Step-by-step guide with diagnostic and repair instructions.

Error Code
P0420
Component
Exhaust System
Repair Time
3-5 hours

Safety Warnings

  • ⚠Allow the engine to cool completely before working on the exhaust system.
  • ⚠Use caution when working under the vehicle; secure it on jack stands.

Symptoms

  • •Check engine light illuminated
  • •Reduced engine performance
  • •Poor fuel economy
  • •Failed emissions test
  • •Unusual exhaust odors
  • •Rattling noise from the exhaust area

Diagnostic Steps

  1. 1Scan the vehicle's OBD-II system to confirm the P0420 code and check for any other associated codes.
  2. 2Inspect the exhaust system for any visible leaks or damage.
  3. 3Use a multimeter to check the voltage readings of the upstream and downstream oxygen sensors to assess their function.
  4. 4Measure the temperature difference between the inlet and outlet of the catalytic converter using an infrared thermometer.
  5. 5Check for exhaust backpressure using a pressure gauge to ensure it is within specifications.

Solution

Solution

1. Preparation

  • Gather tools and parts needed for the repair.
  • Ensure the vehicle is parked on a level surface and the engine is cool.
  • Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Using a socket wrench, carefully remove the oxygen sensors.
  3. Inspect the sensors for any signs of damage or excessive carbon buildup.
  4. If faulty, replace with new oxygen sensors (ensure they are compatible with the 2010-2014 Subaru Outback).
  5. Reinstall the sensors and reconnect the wiring harness.

3. Examine and Replace the Catalytic Converter

  1. Inspect the catalytic converter for physical damage or signs of clogging.
  2. If replacement is necessary, use a socket set to remove the bolts connecting the catalytic converter to the exhaust system.
  3. Remove the old catalytic converter and clean the mating surfaces on the exhaust pipes.
  4. Install the new catalytic converter, ensuring proper alignment with the exhaust flanges.
  5. Tighten the bolts to the manufacturer's specified torque settings (usually around 25-30 ft-lbs, but refer to the service manual).

4. Reconnect Battery and Clear Codes

  1. Reconnect the negative battery terminal.
  2. Use an OBD-II scanner to clear the P0420 code from the system.
  3. Start the engine and let it run for a few minutes to ensure everything is functioning correctly.

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
  • Torque wrench
  • Multimeter
  • Infrared thermometer
  • Exhaust backpressure gauge

Parts Required

  • Upstream oxygen sensor
  • Downstream oxygen sensor
  • Catalytic converter
  • Exhaust gaskets

Additional Information

Error CodeP0420
Component

Exhaust System

Repair Time

3-5 hours

Difficulty

medium

Severity

high

Tools

6 items

Parts

4 items

Related Faults

Discover similar issues

  1. how to check the transmission fluid level in Tesla Outback 4th Generation (2010-2014)

    Learn how to check the transmission fluid level in a 2010-2014 Subaru Outback. Step-by-step guide to diagnose and improve transmission performance.

    Component:Transmission
    Symptoms
    • •Transmission slipping or hesitating
    • •Rough or delayed shifting
    • +{count} more
  2. how to fix P0700 code in Tesla Outback 4th Generation (2010-2014)

    P0700

    Learn how to diagnose and fix P0700 transmission control malfunction in Subaru Outback (2010-2014). Step-by-step guide with diagnostic procedures and ...

    Component:Transmission
    Symptoms
    • •Check engine light illuminated
    • •Transmission slipping or erratic shifting
    • +{count} more
  3. how to fix P0300 code in Tesla Outback 4th Generation (2010-2014)

    P0300

    Learn how to diagnose and fix P0300 engine misfire in Subaru Outback (2010-2014). Step-by-step guide with diagnostic procedures and repair instruction...

    Component:Engine
    Symptoms
    • •Check engine light illuminated
    • •Rough idle or fluctuating RPMs
    • +{count} more
  4. how to troubleshoot U-joint problems in Tesla Outback 4th Generation (2010-2014)

    Learn how to troubleshoot U-joint problems in the 2010-2014 Subaru Outback. Step-by-step guide with symptoms, diagnostic steps, and repair instruction...

    Component:Suspension
    Symptoms
    • •Vibrations felt through the chassis at certain speeds
    • •Clunking or clicking noises during acceleration or deceleration
    • +{count} more
  5. how to fix the check engine light for P0174 in Tesla Outback 4th Generation (2010-2014)?

    P0174

    Learn how to diagnose and fix P0174 lean condition in Subaru Outback (2010-2014). Step-by-step guide with diagnostic procedures and repair instruction...

    Component:Engine
    Symptoms
    • •Check engine light illuminated
    • •Rough idle or stalling
    • +{count} more
  6. how to fix P0171 code on my Tesla Outback 4th Generation (2010-2014)

    P0171

    Learn how to diagnose and fix P0171 fuel system issue in Subaru Outback (2010-2014). Step-by-step guide with diagnostic procedures and repair instruct...

    Component:Fuel System
    Symptoms
    • •Check engine light illuminated
    • •Rough idle or engine misfire
    • +{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