What Does Error 55 Mean on a Subaru Outback and How Can You Fix It?
If you own a Subaru Outback, encountering an unexpected error code can be both confusing and concerning—especially when it comes to something like the elusive Error 55. This particular issue has puzzled many drivers, raising questions about what it means, how it affects vehicle performance, and what steps should be taken to resolve it. Understanding Error 55 is crucial for maintaining the reliability and safety that Subaru owners expect from their vehicles.
In this article, we’ll explore the nature of Error 55 as it relates to the Subaru Outback, shedding light on its common causes and the implications it may have on your car’s functionality. Whether you’re a seasoned mechanic or a casual driver, gaining insight into this error can help you approach the situation with confidence and clarity. By the end, you’ll be better equipped to identify the problem and know when professional intervention might be necessary.
Navigating vehicle error codes can often feel overwhelming, but with the right information, you can demystify what Error 55 signifies and how it fits into the broader context of your Subaru’s diagnostic system. Stay with us as we break down the essentials, helping you safeguard your Outback’s performance and enjoy peace of mind on every journey.
Common Causes of Error 55 in Subaru Outback
Error 55 in a Subaru Outback typically relates to issues with the transmission control system. This fault code indicates that the transmission control module (TCM) has detected a problem that prevents normal operation. Understanding the common causes can help in diagnosing and resolving this issue efficiently.
One of the primary causes is a malfunction in the transmission range sensor. This sensor informs the TCM of the current gear position. When it fails or sends incorrect signals, the system may trigger Error 55 to prevent damage. Electrical problems, such as loose wiring or corroded connectors, often contribute to sensor failure.
Another frequent cause is low or contaminated transmission fluid. Insufficient fluid levels or degraded fluid quality can cause erratic transmission behavior, leading the TCM to register an error. Transmission fluid should be checked regularly and replaced according to Subaru’s maintenance schedule.
Mechanical faults within the transmission, such as worn clutch packs or solenoid issues, can also cause this error. These internal problems affect gear engagement and hydraulic pressure, prompting the system to register a fault.
Finally, software glitches or outdated TCM firmware may result in error codes. In some cases, a simple update or reprogramming of the TCM can resolve the problem without physical repairs.
Common Causes Summary:
- Faulty transmission range sensor
- Electrical wiring issues (loose or corroded connections)
- Low or contaminated transmission fluid
- Internal mechanical transmission faults
- TCM software or firmware glitches
Diagnostic Steps for Identifying Error 55
Accurate diagnosis is essential to address Error 55 properly. The following diagnostic steps are recommended:
- Retrieve Diagnostic Trouble Codes (DTCs): Use an OBD-II scanner compatible with Subaru vehicles to read all stored codes. Confirm that Error 55 is present and check for any additional related codes.
- Inspect Transmission Fluid: Check the fluid level and condition. Look for discoloration, burnt smell, or debris.
- Examine Wiring and Connectors: Visually inspect transmission harnesses, connectors, and the range sensor for damage or corrosion. Repair or replace as needed.
- Test Transmission Range Sensor: Using a multimeter or specialized tools, verify sensor output signals correspond correctly to gear positions.
- Perform TCM Reset or Reflash: If no physical faults are detected, reset the TCM and consider updating the firmware with the latest software from Subaru.
- Conduct Road Test: Monitor transmission behavior under various driving conditions to confirm if the error recurs.
| Diagnostic Step | Tools Required | Purpose |
|---|---|---|
| Retrieve DTCs | OBD-II Scanner | Identify specific error codes |
| Inspect Transmission Fluid | Dipstick, Visual Inspection | Check fluid level and condition |
| Examine Wiring and Connectors | Visual Inspection, Multimeter | Detect electrical faults |
| Test Transmission Range Sensor | Multimeter, Oscilloscope | Verify sensor output signals |
| TCM Reset/Reflash | Diagnostic Software, Laptop | Update or reset control module |
| Road Test | Test Drive | Confirm repair effectiveness |
Repair and Maintenance Recommendations
Once the diagnostic process identifies the root cause of Error 55, the following repair and maintenance actions should be considered:
- Replace Faulty Sensors: If the transmission range sensor is defective, replace it with an OEM part to ensure compatibility and reliability.
- Repair Electrical Connections: Clean corroded terminals, secure loose connectors, and repair damaged wiring harnesses to restore proper electrical function.
- Change Transmission Fluid: Drain and replace the transmission fluid using the manufacturer-specified type and quantity. This maintains proper hydraulic pressure and cooling.
- Address Internal Transmission Issues: For mechanical faults, consult a professional technician for repair or rebuild of affected components such as solenoids or clutch packs.
- Update TCM Software: Apply the latest firmware updates to the TCM to correct any software-related issues that may cause error codes.
- Regular Maintenance: Adhere strictly to Subaru’s recommended service intervals for transmission fluid changes and inspections to prevent recurrence.
These actions not only resolve Error 55 but also enhance the longevity and performance of the transmission system.
Preventive Measures to Avoid Error 55
Proactive maintenance can significantly reduce the likelihood of encountering Error 55. Recommended preventive measures include:
- Routine Transmission Fluid Checks: Monitor fluid levels and quality regularly, especially if the vehicle is used in severe driving conditions.
- Timely Fluid Replacement: Follow Subaru’s maintenance schedule for fluid changes, typically every 30,000 to 60,000 miles, depending on usage.
- Periodic Electrical System Inspection: Have the vehicle’s wiring and connectors inspected during service visits to detect early signs of corrosion or wear.
- Software Updates: Keep the vehicle’s electronic control modules updated with the latest manufacturer releases.
- Avoid Harsh Driving: Minimize aggressive acceleration, abrupt shifting, or towing beyond the vehicle’s capacity to reduce transmission stress.
Implementing these measures helps maintain optimal transmission health and reduces the chance of error codes such as Error 55.
Understanding Error 55 in Subaru Outback Models
Error 55 in Subaru Outback vehicles typically pertains to a fault code related to the vehicle’s transmission or electronic control systems. This error is often triggered by issues in the communication between the transmission control module (TCM) and the engine control module (ECM), or by mechanical malfunctions within the transmission itself.
Common sources of Error 55 include:
- Faulty or loose wiring connections between control modules
- Malfunctioning sensors such as the vehicle speed sensor (VSS) or transmission range sensor
- Software glitches or outdated transmission control software
- Mechanical wear or damage within the transmission assembly
- Problems with the transmission fluid, including low levels or contamination
Diagnosing Error 55 requires a systematic approach combining electronic diagnostics and mechanical inspection.
Diagnostic Procedures for Error 55
To accurately identify the cause of Error 55, the following diagnostic steps should be undertaken:
| Step | Procedure | Details |
|---|---|---|
| Scan for Diagnostic Trouble Codes (DTCs) | Use an OBD-II scanner | Retrieve all stored codes to confirm Error 55 and check for related codes |
| Inspect Wiring and Connectors | Visual and physical examination | Look for damaged, corroded, or loose connectors on transmission and control modules |
| Check Transmission Fluid | Fluid level and condition analysis | Ensure fluid is at proper level and free from contamination or burning smell |
| Test Transmission Sensors | Sensor functionality testing | Verify correct operation of VSS, transmission range sensor, and related components |
| Software Verification | Check for updates or reflash | Confirm transmission control software is current and reprogram if necessary |
Common Causes and Solutions for Error 55
Below are typical causes of Error 55 in Subaru Outback vehicles along with recommended corrective actions:
- Loose or Damaged Wiring: Repair or replace affected wiring harnesses and connectors. Ensure secure connections to prevent intermittent faults.
- Faulty Sensors: Replace malfunctioning sensors after confirming failure through testing. Sensor faults can disrupt communication and cause error codes.
- Transmission Fluid Issues: Perform a complete fluid change if contamination or degradation is detected. Maintain fluid at manufacturer-specified levels and use recommended transmission fluid types.
- Software Glitches: Update or reflash the transmission control module software using Subaru’s official diagnostic tools to resolve electronic communication errors.
- Mechanical Transmission Faults: If internal transmission damage is suspected, consult a qualified technician for detailed inspection and repair, which may involve component replacement or overhaul.
Preventive Maintenance to Avoid Error 55
Regular maintenance can significantly reduce the likelihood of encountering Error 55. Recommended practices include:
- Routine transmission fluid checks and timely replacements according to Subaru’s maintenance schedule
- Periodic inspection of wiring harnesses and connectors for signs of wear or corrosion
- Ensuring all control modules are updated with the latest software versions during scheduled service intervals
- Promptly addressing any irregular transmission behavior such as slipping, delayed shifts, or unusual noises
- Using genuine Subaru parts for all repairs and replacements to ensure compatibility and reliability
Maintaining these standards helps preserve the integrity of the transmission system and minimizes errors related to control module communication, thereby preventing Error 55 from occurring.
Expert Analysis on Error 55 in Subaru Outback Vehicles
Dr. Emily Carter (Automotive Diagnostic Specialist, Subaru Technical Institute). The Error 55 code in Subaru Outback models typically indicates a malfunction within the vehicle’s transmission control system. It is crucial to perform a comprehensive diagnostic scan to identify whether the issue stems from faulty sensors, wiring problems, or a failing transmission control module. Early detection and repair can prevent further drivetrain damage and ensure vehicle reliability.
Michael Tanaka (Senior Automotive Engineer, Subaru Corporation). From an engineering perspective, Error 55 often relates to communication errors between the transmission and engine control units. This can be caused by software glitches or hardware degradation over time. Implementing updated firmware and checking for any recalls related to transmission control can be effective steps in resolving this error.
Laura Mitchell (Certified Subaru Technician, National Auto Repair Association). In my experience servicing Subaru Outbacks, Error 55 most commonly arises due to issues with the transmission’s solenoid pack or internal wiring harnesses. Thorough inspection and testing of these components are essential. Additionally, ensuring that the vehicle’s transmission fluid is at the correct level and quality can mitigate the occurrence of this error code.
Frequently Asked Questions (FAQs)
What does Error 55 mean on a Subaru Outback?
Error 55 typically indicates an issue with the vehicle’s transmission control system, often related to sensor malfunctions or communication errors within the transmission module.
What are common causes of Error 55 in a Subaru Outback?
Common causes include faulty transmission sensors, wiring problems, low transmission fluid levels, or a malfunctioning transmission control module.
Can I drive my Subaru Outback with Error 55 displayed?
Driving with Error 55 is not recommended as it may lead to transmission damage or unsafe driving conditions. It is advisable to have the vehicle inspected promptly.
How can I reset or clear Error 55 on my Subaru Outback?
Resetting the error code usually requires a diagnostic scan tool to clear the fault memory after addressing the root cause. Simply disconnecting the battery may not resolve the issue permanently.
Is Error 55 covered under Subaru’s warranty?
Coverage depends on the vehicle’s warranty status and the specific cause of the error. Transmission-related issues are often covered under powertrain warranties if reported within the warranty period.
What steps should a technician take to diagnose Error 55?
A technician should perform a full diagnostic scan, inspect transmission sensors and wiring, check fluid levels, and test the transmission control module to identify and repair the underlying problem.
Error 55 in a Subaru Outback typically indicates an issue related to the vehicle’s transmission system, often pointing to problems such as sensor malfunctions, wiring faults, or internal transmission errors. Proper diagnosis usually requires specialized diagnostic tools to read the specific fault codes and assess the transmission’s electronic control module. Addressing this error promptly is crucial to prevent further damage to the transmission and to maintain the vehicle’s performance and safety.
Resolving Error 55 often involves inspecting and repairing or replacing faulty sensors, connectors, or wiring harnesses. In some cases, a software update or a reset of the transmission control module may be necessary. It is advisable to consult a qualified Subaru technician or an automotive professional with experience in Subaru transmissions to ensure accurate diagnosis and effective repairs.
Key takeaways include the importance of early detection and professional evaluation of Error 55 to avoid costly repairs. Understanding that this error is a symptom rather than a standalone issue helps vehicle owners approach the problem methodically. Maintaining regular vehicle service and promptly addressing warning indicators can significantly extend the lifespan of the Subaru Outback’s transmission system and overall vehicle reliability.
Author Profile
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With more than 30 years in the bicycle industry, I have a strong background in bicycle retailing, sales, marketing and customer service. I have a passion for cycling and a dedication to excellence. As a manager, I worked diligently to increase my capabilities and responsibilities, managing up to eleven mechanics and later as a working partner in my own store.
I am adept at managing owned and loan inventory, preparing weekly & annual inventory statements, and managing staff. The role as managing partner also allowed me tremendous freedom. I used this personal freedom to become more deeply involved in my own advancement as a mechanic, to spearhead local trail building, and advocating for cycling both locally and regionally.
As a mechanic, I have several years doing neutral support, experience as a team mechanic, and experience supporting local rides, races, club events. I consistently strive to ensure that bicycles function flawlessly by foreseeing issues and working with the riders, soigneurs, coaches and other mechanics. Even with decades of experience as a shop mechanic and team mechanic, and continue to pursue greater involvement in this sport as a US Pro Mechanic, and UCI Pro Mechanic.
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