What Are Common Subaru Trouble Codes and How to Fix Them?

Subaru Trouble Codes offer a vital starting point for diagnosing issues in your vehicle, allowing technicians and owners to pinpoint problems efficiently. At CAR-TOOL.EDU.VN, we provide comprehensive resources to help you understand these codes and potential solutions, ensuring your Subaru receives the best care and maintains optimal performance. Understanding these codes enables accurate diagnostics, efficient repairs, and ultimately, a smoother and safer driving experience.

1. What are Subaru Trouble Codes and Why are They Important?

Subaru trouble codes are alphanumeric identifiers generated by your vehicle’s onboard diagnostic system (OBD-II) when it detects a malfunction. These codes are crucial because they provide a starting point for diagnosing and repairing issues, saving time and money by guiding technicians directly to the source of the problem. According to a study by the National Institute for Automotive Service Excellence (ASE), accurate initial diagnosis can reduce repair time by up to 40%.

• Definition of OBD-II System: The OBD-II system is a standardized system used in most vehicles since 1996 to monitor the performance of the engine, transmission, and other components. When a problem is detected, the system stores a trouble code and may illuminate the check engine light on the dashboard.
• Importance of Understanding Trouble Codes: Understanding these codes is essential for vehicle owners and technicians alike. For owners, it provides insight into potential problems, allowing them to communicate effectively with repair professionals. For technicians, it streamlines the diagnostic process, leading to quicker and more accurate repairs.
• Benefits of Early Diagnosis: Early diagnosis of issues identified by trouble codes can prevent minor problems from escalating into major, more costly repairs. It also ensures the vehicle operates efficiently, reducing fuel consumption and emissions.

2. Where Can I Find a Comprehensive List of Subaru Trouble Codes?

A comprehensive list of Subaru trouble codes can be found on several authoritative websites and databases, including CAR-TOOL.EDU.VN. These resources provide detailed information on each code, including possible causes, symptoms, and potential solutions. Accessing these lists helps both car owners and technicians understand the nature of the problem and plan the necessary repairs.

• Online Databases and Websites: Websites such as OBD-Codes.com and CAR-TOOL.EDU.VN offer extensive databases of OBD-II codes, including Subaru-specific codes. These sites often include detailed descriptions, possible causes, and potential fixes.
• Official Subaru Repair Manuals: Official Subaru repair manuals provide the most accurate and detailed information on trouble codes for specific models. These manuals are available for purchase from Subaru dealerships or online.
• OBD-II Scanner Tools: Many OBD-II scanner tools come with built-in databases of trouble codes. These scanners can read the codes directly from your vehicle’s computer and provide descriptions and possible solutions on the spot.

3. How Do I Use an OBD-II Scanner to Read Subaru Trouble Codes?

Using an OBD-II scanner to read Subaru trouble codes is a straightforward process. Here’s a step-by-step guide to help you retrieve and understand the codes:

1. Locate the OBD-II Port: The OBD-II port is typically located under the dashboard on the driver’s side.
2. Plug in the Scanner: Plug the OBD-II scanner into the port.
3. Turn on the Ignition: Turn the ignition to the “on” position without starting the engine.
4. Follow the Scanner’s Instructions: The scanner will prompt you to read the codes. Follow the on-screen instructions to retrieve the stored trouble codes.
5. Record the Codes: Write down the codes that the scanner displays.
6. Consult a Trouble Code Database: Use an online database or the scanner’s built-in database to look up the meaning of each code.

4. What are the Most Common Subaru Trouble Codes and Their Meanings?

Several trouble codes frequently appear in Subaru vehicles, each indicating specific issues. Understanding these common codes can help you quickly identify and address problems.

Code	Description	Possible Causes
P0011	“A” Camshaft Position Timing Over-Advanced or System Performance (Bank 1)	Low engine oil level, incorrect engine timing, faulty camshaft timing solenoid, worn timing chain.
P0171	System Too Lean (Bank 1)	Vacuum leaks, faulty mass airflow sensor, plugged fuel filter, weak fuel pump, dirty fuel injectors.
P0301	Cylinder 1 Misfire Detected	Worn spark plugs, ignition wires, or coils, vacuum leaks, low fuel pressure, defective mass airflow sensor, faulty crankshaft or camshaft sensor, mechanical engine problems.
P0420	Catalyst System Efficiency Below Threshold (Bank 1)	Inefficient catalytic converter, defective oxygen sensors, misfiring engine.
P0442	Evaporative Emission Control System Leak Detected (small leak)	Defective fuel cap, damaged fuel tank filler neck, small tears in evaporative system hoses, defective fuel tank sending unit gasket, faulty evaporative vent valve.
P0500	Vehicle Speed Sensor A	Defective vehicle speed sensor, faulty speedometer, wiring or connector issues, communication bus problems, defective transmission or differential speed sensor drive gear.
P0010	Powertrain Control Module (PCM) failure, Variable valve timing actuator failure, Wiring issue
P0013	Powertrain Control Module (PCM) failure, Variable valve timing actuator failure, Wiring issue
P0101	Large vacuum leaks, Split Intake Air Boot or PCV Hose, Defective intake manifold gaskets, Mass Airflow Sensor (MAF), Mass Air Flow Sensor circuit and or wiring problems, Defective Barometric Pressure Sensor, Dirty or contaminated Mass Air Flow Sensing wire or filament, PCM software needs to be updated
P0102	The Mass Airflow Sensor (MAF) Sensor is unplugged or the wiring is damaged, Loose or corroded electrical terminals in the MAF Sensor circuit, Faulty MAF Sensor

5. What Does Trouble Code P0011 Mean for My Subaru?

Trouble code P0011 indicates “A” Camshaft Position Timing Over-Advanced or System Performance (Bank 1). This code suggests that the camshaft in Bank 1 is more advanced than the engine control unit (ECU) is commanding it to be. According to a study by the Society of Automotive Engineers (SAE), issues with variable valve timing systems are increasingly common due to their complexity and sensitivity to oil quality.

• Symptoms of P0011: Common symptoms include a rough idle, decreased fuel economy, reduced engine power, and the check engine light being illuminated.
• Possible Causes: The most likely causes are low engine oil level, incorrect engine timing, a faulty camshaft timing solenoid, or a worn timing chain.
• Troubleshooting Steps:
  1. Check the engine oil level and condition.
  2. Inspect the camshaft timing solenoid for proper operation.
  3. Verify the engine timing is correct.
  4. Inspect the timing chain for wear.

6. How Do I Fix Trouble Code P0171 (System Too Lean) in a Subaru?

Trouble code P0171 indicates that the engine is running too lean, meaning there is too much air and not enough fuel in the air-fuel mixture. Addressing this code promptly is crucial for maintaining engine health and efficiency.

• Common Symptoms of P0171: Common symptoms include the check engine light, rough idle, hesitation during acceleration, and decreased fuel economy.
• Step-by-Step Solutions:
  1. Check for Vacuum Leaks: Inspect all vacuum hoses and intake manifold gaskets for leaks. Use a smoke machine to identify hard-to-find leaks.
  2. Inspect the Mass Airflow Sensor (MAF): Clean the MAF sensor with a specialized MAF sensor cleaner. If cleaning doesn’t help, consider replacing the sensor.
  3. Check Fuel Filter and Fuel Pump: Replace the fuel filter if it’s clogged. Test the fuel pump to ensure it’s delivering adequate pressure.
  4. Clean or Replace Fuel Injectors: Use a fuel injector cleaner additive. If the problem persists, have the injectors professionally cleaned or replaced.

7. What Should I Do if My Subaru Shows Trouble Code P0301 (Cylinder 1 Misfire)?

Trouble code P0301 indicates that there is a misfire in cylinder 1. A misfire means that the cylinder is not firing correctly, which can lead to rough running and potential engine damage.

• Identifying the Symptoms: Common symptoms include rough idle, noticeable loss of power, the check engine light flashing, and a smell of fuel.
• Diagnostic and Repair Steps:
  1. Check the Spark Plugs: Inspect the spark plug in cylinder 1. Replace it if it’s worn, fouled, or damaged.
  2. Inspect Ignition Wires and Coils: Check the ignition wire and coil for cylinder 1. Replace if damaged or faulty.
  3. Check for Vacuum Leaks: Use a vacuum gauge to check for vacuum leaks around the intake manifold and hoses.
  4. Check Fuel Injector: Test the fuel injector for cylinder 1. Clean or replace if necessary.

8. What Does Trouble Code P0420 Mean and How Can I Resolve It?

Trouble code P0420 indicates “Catalyst System Efficiency Below Threshold (Bank 1).” This means the catalytic converter is not functioning efficiently, which can lead to increased emissions and potential damage to other engine components.

• Understanding the Code: This code suggests that the catalytic converter is not properly reducing pollutants in the exhaust.
• Troubleshooting and Solutions:
  1. Inspect the Catalytic Converter: Visually inspect the catalytic converter for damage.
  2. Check Oxygen Sensors: Test the oxygen sensors before and after the catalytic converter. Replace if faulty.
  3. Check for Exhaust Leaks: Repair any exhaust leaks before the catalytic converter, as these can affect its performance.
  4. Consider Catalytic Converter Replacement: If the catalytic converter is old or damaged, replacement may be necessary. According to the EPA, catalytic converters are designed to last for approximately 100,000 miles.

9. How Can I Fix Trouble Code P0442 (Small Evaporative Leak) in My Subaru?

Trouble code P0442 indicates “Evaporative Emission Control System Leak Detected (small leak).” This code suggests there is a small leak in the evaporative emission control system, which prevents fuel vapors from escaping into the atmosphere.

• Symptoms of P0442: Common symptoms include the check engine light being illuminated and, in some cases, a slight smell of fuel.
• Troubleshooting Steps:
  1. Check the Fuel Cap: Ensure the fuel cap is properly tightened and not damaged. Replace if necessary.
  2. Inspect Evaporative System Hoses: Check all hoses in the evaporative system for cracks or damage. Replace if necessary.
  3. Check the Fuel Tank Sending Unit Gasket: Inspect the fuel tank sending unit gasket for leaks. Replace if necessary.
  4. Inspect the Evaporative Vent Valve: Test the evaporative vent valve for proper operation. Replace if faulty.

10. What Steps Should I Take for Trouble Code P0500 (Vehicle Speed Sensor)?

Trouble code P0500 indicates a problem with the Vehicle Speed Sensor (VSS). This sensor is crucial for various functions, including speedometer operation, transmission shifting, and cruise control.

• Identifying the Problem: Common symptoms include a malfunctioning speedometer, erratic shifting, cruise control not working, and the check engine light.
• Diagnostic and Repair Procedures:
  1. Check the Vehicle Speed Sensor: Inspect the VSS for damage and ensure it’s properly connected. Replace if necessary.
  2. Inspect Wiring and Connectors: Check the wiring and connectors leading to the VSS for damage or corrosion. Repair or replace as needed.
  3. Check the Speedometer: Test the speedometer to ensure it’s functioning correctly. If not, the problem may lie with the instrument cluster.
  4. Check Transmission and Differential: Inspect the transmission and differential speed sensor drive gear for damage.

11. Are There Subaru-Specific Trouble Codes I Should Be Aware Of?

Yes, Subaru has specific trouble codes, often starting with “P1XXX,” which are not part of the standard OBD-II protocol. These codes relate to systems and components unique to Subaru vehicles and require specialized knowledge to diagnose and repair.

• Examples of Subaru-Specific Codes: These codes can relate to Subaru’s Symmetrical All-Wheel Drive system, the Boxer engine, or other proprietary technologies.
• Importance of Professional Diagnosis: Due to the complexity and specificity of these codes, it’s often best to seek diagnosis and repair from a certified Subaru technician.

12. How Do I Prevent Common Subaru Trouble Codes from Occurring?

Preventing trouble codes involves regular maintenance and care to ensure your Subaru’s systems are functioning optimally.

• Regular Maintenance Tips:
  • Regular Oil Changes: Follow Subaru’s recommended oil change intervals. According to Subaru, synthetic oil should be used in many of their newer models.
  • Check and Replace Fluids: Regularly check and replace transmission fluid, coolant, and brake fluid.
  • Inspect Hoses and Belts: Regularly inspect hoses and belts for cracks, wear, and damage.
  • Check and Clean Sensors: Periodically check and clean sensors such as the MAF sensor and oxygen sensors.
• Driving Habits: Avoid aggressive driving, which can strain the engine and other components.
• Quality Parts and Fluids: Use high-quality parts and fluids that meet Subaru’s specifications.

13. Where Can I Find Reliable Subaru Parts to Fix Trouble Codes?

Finding reliable Subaru parts is essential for ensuring lasting repairs. CAR-TOOL.EDU.VN offers a wide range of high-quality parts to address various trouble codes.

• Authorized Subaru Dealerships: Authorized dealerships provide genuine Subaru parts, ensuring the best fit and performance.
• Reputable Online Retailers: Online retailers such as CAR-TOOL.EDU.VN offer a wide selection of Subaru parts, often at competitive prices.
• Local Auto Parts Stores: Local auto parts stores can provide quick access to common replacement parts.

14. What Tools Do I Need to Diagnose and Fix Subaru Trouble Codes?

Having the right tools can make diagnosing and fixing Subaru trouble codes much easier. CAR-TOOL.EDU.VN offers a variety of tools to assist with these tasks.

• Essential Tools:
  • OBD-II Scanner: For reading and clearing trouble codes.
  • Multimeter: For testing electrical components.
  • Vacuum Gauge: For checking for vacuum leaks.
  • Socket Set: For removing and installing various components.
  • Wrench Set: For tightening and loosening bolts and nuts.
• Specialty Tools: Depending on the repair, you may need specialty tools such as a timing light, compression tester, or fuel pressure tester.

15. When Should I Consult a Professional Mechanic for Subaru Trouble Codes?

While some trouble codes can be resolved with basic maintenance and repairs, others require the expertise of a professional mechanic.

• When to Seek Professional Help:
  • Complex Codes: If the trouble code indicates a complex issue that you’re not comfortable addressing.
  • Unfamiliar with Repairs: If you’re not experienced with automotive repairs.
  • Recurring Codes: If the same trouble code keeps returning after you’ve attempted to fix it.
  • Safety Concerns: If the issue affects the vehicle’s safety, such as braking or steering.
• Benefits of Professional Service: Professional mechanics have the training, experience, and equipment to accurately diagnose and repair complex issues, ensuring the job is done right.

16. What is the Cost of Diagnosing and Repairing Common Subaru Trouble Codes?

The cost of diagnosing and repairing Subaru trouble codes can vary widely depending on the specific code, the complexity of the repair, and the labor rates in your area.

• Factors Affecting Cost:
  • Diagnostic Fees: Most shops charge a diagnostic fee to identify the source of the problem. This fee can range from $75 to $150.
  • Parts Costs: The cost of replacement parts can vary significantly depending on the part and the brand.
  • Labor Costs: Labor rates vary by location, but typically range from $80 to $150 per hour.
• Estimating Repair Costs: Contact several local repair shops to get estimates for the specific trouble code you’re dealing with.

17. Can Clearing Subaru Trouble Codes Without Fixing the Problem Cause Damage?

Yes, clearing Subaru trouble codes without fixing the underlying problem can potentially cause damage to your vehicle. While it may temporarily turn off the check engine light, the issue will likely return, and continued operation with the problem can lead to more severe damage.

• Why It’s Risky: Clearing the code doesn’t address the root cause of the issue. The problem may worsen over time, leading to more costly repairs.
• Potential Consequences: Ignoring trouble codes can result in decreased fuel economy, reduced engine performance, and potential damage to critical components such as the engine, transmission, or catalytic converter.

18. What is the Role of the Powertrain Control Module (PCM) in Subaru Trouble Codes?

The Powertrain Control Module (PCM) is the central computer in your Subaru that controls the engine and transmission. It plays a crucial role in generating and interpreting trouble codes.

• PCM Functions: The PCM monitors various sensors throughout the vehicle and uses this information to optimize engine performance, fuel economy, and emissions.
• Impact on Trouble Codes: When a sensor reading falls outside of acceptable parameters, the PCM generates a trouble code and stores it in its memory.
• PCM Issues: In some cases, the PCM itself can be the source of trouble codes. A faulty PCM may generate false codes or fail to properly diagnose issues.

19. How Do Oxygen Sensors Affect Subaru Trouble Codes and Engine Performance?

Oxygen sensors play a critical role in monitoring the exhaust gases and providing feedback to the PCM, which adjusts the air-fuel mixture accordingly. Faulty oxygen sensors can lead to various trouble codes and negatively affect engine performance.

• Function of Oxygen Sensors: Oxygen sensors measure the amount of oxygen in the exhaust and send this information to the PCM.
• Impact on Air-Fuel Mixture: The PCM uses this information to adjust the air-fuel mixture, ensuring optimal combustion.
• Trouble Codes Related to Oxygen Sensors: Common trouble codes related to oxygen sensors include P0135, P0171, and P0420.
• Symptoms of Faulty Oxygen Sensors: Common symptoms include decreased fuel economy, rough idle, and the check engine light being illuminated.

20. How Can I Use a Subaru Trouble Code to Improve Fuel Efficiency?

Addressing trouble codes promptly can significantly improve your Subaru’s fuel efficiency. Many trouble codes indicate issues that can negatively impact fuel economy, such as a lean air-fuel mixture, misfires, or a faulty oxygen sensor.

• Identifying Fuel Efficiency Issues: Use an OBD-II scanner to identify trouble codes that may be affecting fuel efficiency.
• Addressing Common Codes:
  • P0171 (System Too Lean): Fix vacuum leaks, clean or replace the MAF sensor, and check the fuel filter and fuel pump.
  • P0301 (Cylinder 1 Misfire): Replace worn spark plugs, ignition wires, or coils.
  • P0420 (Catalyst System Efficiency Below Threshold): Replace the catalytic converter if necessary and check the oxygen sensors.
• Regular Maintenance: Follow Subaru’s recommended maintenance schedule to keep your vehicle running efficiently.

21. What are the Potential Long-Term Effects of Ignoring Subaru Trouble Codes?

Ignoring Subaru trouble codes can lead to a variety of long-term problems, including reduced engine life, increased repair costs, and potential safety hazards.

• Engine Damage: Continued operation with unresolved issues can cause significant engine damage.
• Increased Emissions: Ignoring emission-related trouble codes can lead to increased pollution and potential fines.
• Safety Hazards: Some trouble codes can indicate problems that affect the vehicle’s safety, such as braking or steering issues.
• Reduced Resale Value: A vehicle with unresolved trouble codes may have a lower resale value.

22. How Can CAR-TOOL.EDU.VN Help Me with Subaru Trouble Codes?

CAR-TOOL.EDU.VN provides a wealth of resources to help you understand and address Subaru trouble codes.

• Comprehensive Information: We offer detailed information on a wide range of trouble codes, including possible causes, symptoms, and solutions.
• High-Quality Parts: We provide access to high-quality Subaru parts to ensure lasting repairs.
• Expert Advice: Our team of experienced technicians can provide expert advice and guidance to help you diagnose and repair your vehicle.
• Tools and Equipment: We offer a variety of tools and equipment to assist with diagnosing and fixing trouble codes.

23. What is the Difference Between Generic and Enhanced Subaru Trouble Codes?

Generic OBD-II codes are standardized codes that apply to all vehicles, while enhanced codes are manufacturer-specific and provide more detailed information about the issue.

• Generic Codes: These codes are the same across all makes and models and provide a basic indication of the problem.
• Enhanced Codes: These codes are specific to Subaru vehicles and offer more detailed information about the affected system or component.
• Benefits of Enhanced Codes: Enhanced codes can help technicians diagnose issues more accurately and efficiently.

24. How Do I Reset the Check Engine Light After Fixing a Subaru Trouble Code?

After fixing a Subaru trouble code, you’ll need to reset the check engine light to clear the code from the PCM’s memory.

• Using an OBD-II Scanner:
  1. Plug the scanner into the OBD-II port.
  2. Turn the ignition to the “on” position without starting the engine.
  3. Follow the scanner’s instructions to clear the trouble codes.
• Disconnecting the Battery:
  1. Disconnect the negative battery cable.
  2. Wait 15-20 minutes.
  3. Reconnect the battery cable.

25. Can Cold Weather Affect Subaru Trouble Codes?

Yes, cold weather can affect Subaru trouble codes, particularly those related to the engine and emissions systems.

• Common Cold Weather Issues:
  • P0128 (Coolant Thermostat Below Regulating Temperature): Cold weather can prevent the engine from reaching its operating temperature quickly enough, triggering this code.
  • Battery Issues: Cold weather can reduce battery performance, leading to various electrical trouble codes.
  • Sensor Issues: Some sensors may not function correctly in extreme cold.
• Preventive Measures:
  • Ensure Proper Coolant Mix: Use the correct coolant-to-water ratio to prevent freezing.
  • Check Battery Health: Have the battery tested to ensure it’s in good condition.
  • Use a Block Heater: Consider using an engine block heater in extremely cold conditions.

26. Are There Any Recalls Related to Common Subaru Trouble Codes?

It’s essential to check for recalls related to common Subaru trouble codes, as some issues may be covered by the manufacturer.

• How to Check for Recalls:
  • Subaru Website: Visit the official Subaru website and enter your VIN to check for recalls.
  • NHTSA Website: Visit the National Highway Traffic Safety Administration (NHTSA) website and enter your VIN.
• Benefits of Addressing Recalls: Recalls are typically performed free of charge and can address safety-related issues or common problems with specific models.

27. Can Aftermarket Accessories Cause Subaru Trouble Codes?

Yes, aftermarket accessories can sometimes cause Subaru trouble codes, particularly if they interfere with the vehicle’s electrical or emissions systems.

• Common Culprits:
  • Performance Chips: Aftermarket performance chips can alter engine parameters and trigger trouble codes.
  • Electrical Accessories: Aftermarket stereos, alarms, or lighting systems can cause electrical issues.
  • Exhaust Modifications: Modifications to the exhaust system can affect emissions and trigger trouble codes.
• Troubleshooting Tips:
  • Disconnect Accessories: Try disconnecting the aftermarket accessory to see if the trouble code disappears.
  • Check Wiring: Ensure the accessory is properly wired and not interfering with other systems.
  • Consult a Professional: If you’re unsure, consult a professional mechanic.

28. How Do Subaru’s Symmetrical All-Wheel Drive System Affect Trouble Codes?

Subaru’s Symmetrical All-Wheel Drive (AWD) system is a unique feature that can sometimes influence the types of trouble codes that appear.

• AWD-Related Codes: Some trouble codes are specific to the AWD system, such as those related to the transfer case or differential.
• Impact on Diagnostics: When diagnosing trouble codes on a Subaru with AWD, it’s essential to consider the potential involvement of the AWD system.
• Professional Expertise: Diagnosing AWD-related issues often requires specialized knowledge and equipment, so it’s best to consult a professional mechanic.

29. What Role Does the Subaru Boxer Engine Play in Common Trouble Codes?

The Subaru Boxer engine, with its unique horizontally opposed design, can influence certain trouble codes.

• Engine-Specific Codes: Some trouble codes are more common in Boxer engines due to their design, such as those related to cylinder misfires or oil leaks.
• Maintenance Considerations: Proper maintenance, including regular oil changes and spark plug replacements, is crucial for preventing trouble codes in Boxer engines.
• Expertise Required: Diagnosing issues specific to the Boxer engine often requires expertise and specialized tools.

30. How Can I Keep My Subaru Running Smoothly and Avoid Trouble Codes?

Keeping your Subaru running smoothly and avoiding trouble codes involves a combination of regular maintenance, careful driving habits, and prompt attention to any potential issues.

• Key Maintenance Practices:
  • Follow the Recommended Service Schedule: Adhere to Subaru’s recommended maintenance schedule for oil changes, fluid checks, and other services.
  • Use Quality Parts and Fluids: Use high-quality parts and fluids that meet Subaru’s specifications.
  • Inspect Regularly: Regularly inspect your vehicle for any signs of wear, leaks, or damage.
• Driving Tips:
  • Avoid Aggressive Driving: Avoid harsh acceleration, braking, and cornering.
  • Warm Up the Engine: Allow the engine to warm up before driving in cold weather.
• Address Issues Promptly: If you notice any unusual symptoms or the check engine light comes on, address the issue promptly to prevent further damage.

For reliable Subaru parts and expert advice, visit CAR-TOOL.EDU.VN. Our team is dedicated to helping you keep your Subaru running smoothly and efficiently. Contact us today at +1 (641) 206-8880 or visit us at 456 Elm Street, Dallas, TX 75201, United States.

FAQ: Subaru Trouble Codes

Q1: What do Subaru trouble codes signify?
Subaru trouble codes are alphanumeric codes generated by the vehicle’s onboard diagnostic system (OBD-II) to indicate malfunctions in various systems like the engine, transmission, or emissions. These codes help pinpoint the source of the problem.

Q2: How can I read Subaru trouble codes?
You can read Subaru trouble codes using an OBD-II scanner. Plug the scanner into the OBD-II port, turn on the ignition, and follow the scanner’s instructions to retrieve the stored codes.

Q3: What is the meaning of Subaru trouble code P0011?
Subaru trouble code P0011 indicates “A” Camshaft Position Timing Over-Advanced or System Performance (Bank 1), suggesting the camshaft in Bank 1 is more advanced than the ECU commands.

Q4: How do I fix Subaru trouble code P0171 (System Too Lean)?
To fix Subaru trouble code P0171, check for vacuum leaks, inspect the mass airflow sensor (MAF), check the fuel filter and fuel pump, and clean or replace the fuel injectors.

Q5: What should I do if my Subaru shows trouble code P0301 (Cylinder 1 Misfire)?
If your Subaru shows trouble code P0301, check the spark plugs, ignition wires and coils, look for vacuum leaks, and inspect the fuel injector for cylinder 1.

Q6: What does Subaru trouble code P0420 mean?
Subaru trouble code P0420 means “Catalyst System Efficiency Below Threshold (Bank 1),” indicating that the catalytic converter is not functioning efficiently.

Q7: How can I fix Subaru trouble code P0442 (Small Evaporative Leak)?
To fix Subaru trouble code P0442, check the fuel cap, inspect evaporative system hoses, check the fuel tank sending unit gasket, and inspect the evaporative vent valve.

Q8: What steps should I take for Subaru trouble code P0500 (Vehicle Speed Sensor)?
For Subaru trouble code P0500, check the vehicle speed sensor (VSS), inspect wiring and connectors, check the speedometer, and check the transmission and differential.

Q9: Are there Subaru-specific trouble codes I should be aware of?
Yes, Subaru has specific trouble codes, often starting with “P1XXX,” which are not part of the standard OBD-II protocol and relate to systems unique to Subaru vehicles.

Q10: When should I consult a professional mechanic for Subaru trouble codes?
Consult a professional mechanic for complex codes, if you’re unfamiliar with repairs, if the same codes recur, or if the issue affects vehicle safety.

Don’t let trouble codes keep you off the road. Contact CAR-TOOL.EDU.VN today for expert advice and quality Subaru parts. Call us at +1 (641) 206-8880 or visit our location at 456 Elm Street, Dallas, TX 75201, United States. Your Subaru deserves the best care.