Allison Transmission Fault Code Spn 2003 Fmi 31 : Troubleshooting Tips. - Survival Savior (2024)

The Allison transmission fault code SPN 2003 FMI 31 indicates a fault with the transmission speed sensor. This fault code can be resolved by replacing the faulty speed sensor.

In some cases, the fault code may require further diagnosis to determine the exact cause of the issue. Allison Transmission fault codes can help identify issues with the transmission system in a vehicle. One such code is SPN 2003 FMI 31, which relates to a fault with the transmission speed sensor.

When this code is displayed, it indicates that the speed sensor is not functioning properly. The speed sensor plays a crucial role in monitoring the speed of the vehicle and providing feedback to the transmission control unit. This information helps ensure smooth gear shifting and overall performance of the transmission. Resolving the SPN 2003 FMI 31 code involves replacing the faulty speed sensor, although additional troubleshooting may be necessary to determine the root cause of the issue.

Allison Transmission Fault Code Spn 2003 Fmi 31 : Troubleshooting Tips. - Survival Savior (1)

Contents hide

  • Understanding Spn 2003 Fmi 31
  • Common Causes Of Spn 2003 Fmi 31
  • Diagnostic Process
  • Troubleshooting Steps
  • Professional Maintenance
  • Frequently Asked Questions For Allison Transmission Fault Code Spn 2003 Fmi 31
  • Conclusion

Understanding Spn 2003 Fmi 31

SPN 2003 FMI 31 is an Allison Transmission fault code that indicates a problem with the vehicle’s gearbox. Understanding this code is crucial for diagnosing and repairing transmission issues efficiently, ensuring smooth operation and safety on the road.

What Is Spn 2003?

SPN 2003 refers to a specific fault code used in Allison transmissions. It is a diagnostic code that helps to identify and troubleshoot issues within the transmission system. This code is part of the Society of Automotive Engineers (SAE) standard J1939, which is used to communicate diagnostic information between different vehicle components.

What Is Fmi 31?

FMI 31 stands for Failure Mode Indicator 31. In the context of SPN 2003, FMI 31 represents a specific type of fault or failure mode that is associated with this fault code. The FMI is a predefined set of codes that provide additional information about the nature of the fault. In this case, FMI 31 indicates an improper configuration or a parameter that is out of range.

Now that we understand what SPN 2003 and FMI 31 mean, let’s delve deeper into the specifics of SPN 2003 FMI 31.

Allison Transmission Fault Code Spn 2003 Fmi 31 : Troubleshooting Tips. - Survival Savior (2)


Common Causes Of Spn 2003 Fmi 31

If you are experiencing the SPN 2003 FMI 31 fault code on your Allison Transmission, it is important to understand the common causes behind it. By identifying these causes, you can take the necessary steps to resolve the issue and ensure the smooth operation of your transmission. Let’s dive into the possible reasons:

Low Transmission Fluid Level

One of the common causes of the SPN 2003 FMI 31 fault code is a low transmission fluid level. Having an insufficient amount of fluid in the transmission can lead to various issues, including improper shifting, slipping gears, and increased friction. To check the fluid level, locate the transmission dipstick and ensure it is within the recommended range. If it is below the recommended level, it is crucial to add the appropriate amount of fluid as per your vehicle’s specifications. Remember to use the correct type of transmission fluid, which can usually be found in your vehicle’s owner’s manual.

Faulty Shift Solenoid

Another possible cause of the SPN 2003 FMI 31 fault code is a faulty shift solenoid. The shift solenoid is responsible for controlling the flow of transmission fluid and engaging the appropriate gears for smooth shifting. When the solenoid malfunctions, it can disrupt the shifting process and result in the fault code. If you suspect a faulty shift solenoid, it is recommended to have your transmission inspected by a qualified technician. They will be able to diagnose the issue and determine if the solenoid needs to be replaced.

In conclusion, it is essential to address the common causes behind the SPN 2003 FMI 31 fault code in your Allison Transmission. Keeping an eye on the transmission fluid level and ensuring it is within the recommended range will help prevent issues related to low fluid. Additionally, if you suspect a faulty shift solenoid, seeking professional assistance will ensure proper diagnosis and resolution of the problem.

Diagnostic Process

When dealing with a transmission fault code like Allison SPN 2003 FMI 31, the diagnostic process is crucial to identify and resolve the issue effectively. Understanding how to use diagnostic tools and interpret error codes is essential for a successful resolution. Let’s delve into the diagnostic process for addressing Allison Transmission fault code SPN 2003 FMI 31.

Using Diagnostic Tools

Utilizing diagnostic tools is the initial step in the diagnostic process. There are various diagnostic tools available in the market that are specially designed for assessing transmission faults. These tools help in scanning the vehicle’s system to pinpoint the exact nature of the issue, allowing for a more accurate diagnosis.

Interpreting Error Codes

Interpreting error codes is a critical aspect of the diagnostic process. Once the diagnostic tool has scanned the system, it generates error codes that provide specific details about the problem. Understanding what these error codes indicate is essential for determining the appropriate course of action. By deciphering the error codes, technicians can identify the root cause of the transmission fault and proceed with the necessary repairs.

Troubleshooting Steps

When encountering the Allison Transmission fault code SPN 2003 FMI 31, a systematic approach to troubleshooting is crucial. Follow these steps to efficiently diagnose and resolve the issue:

Fluid Level Inspection

1. Park the vehicle on a level surface and engage the parking brake.

2. Locate the transmission fluid dipstick and check the fluid level following the manufacturer’s guidelines.

3. Ensure the fluid level is within the recommended range to avoid potential issues.

Solenoid Function Testing

1. Identify the solenoid related to the fault code by referring to the transmission manual.

2. Use a multimeter to test the solenoid’s resistance and compare it to the specified values.

3. If the solenoid fails the resistance test, consider replacing it to resolve the fault code.

Professional Maintenance

Allison Transmission Fault Code Spn 2003 Fmi 31 may require professional maintenance expertise for intricate troubleshooting.

Seeking Expert Assistance

When faced with complex transmission fault codes, reaching out to qualified technicians is advisable for accurate diagnosis.

Preventive Maintenance Tips

  • Regularly inspecting transmission components
  • Following manufacturer-recommended service schedules
  • Monitoring fluid levels and quality
  • Addressing any issues promptly

Proactive Steps

Proper maintenance is key to extending the lifespan and efficient performance of your Allison transmission system.

Allison Transmission Fault Code Spn 2003 Fmi 31 : Troubleshooting Tips. - Survival Savior (3)


Allison Transmission Fault Code Spn 2003 Fmi 31 : Troubleshooting Tips. - Survival Savior (4)


Frequently Asked Questions For Allison Transmission Fault Code Spn 2003 Fmi 31

What Is The Meaning Of Allison Transmission Fault Code Spn 2003 Fmi 31?

Allison Transmission Fault Code Spn 2003 Fmi 31 indicates a specific issue with the transmission system relating to a parameter or function. It’s crucial to diagnose and address this fault code promptly to prevent potential damage to the transmission.

How Can I Troubleshoot Allison Transmission Fault Code Spn 2003 Fmi 31?

To troubleshoot Allison Transmission Fault Code Spn 2003 Fmi 31, perform a thorough inspection of the transmission components, check for loose connections, verify fluid levels, and consult the manufacturer’s manual for specific diagnostic procedures. Seeking professional assistance is advisable if needed.

What Are The Potential Consequences Of Ignoring Allison Transmission Fault Code Spn 2003 Fmi 31?

Ignoring Allison Transmission Fault Code Spn 2003 Fmi 31 can lead to further damage to the transmission system, reduced performance, and safety risks. Addressing this fault promptly can prevent costly repairs and ensure the optimal functioning of the transmission.


Dealing with Allison transmission fault code SPN 2003 FMI 31 can be challenging but manageable with proper diagnosis and troubleshooting. Understanding the root cause and following the recommended steps can help resolve the issue effectively. By addressing SPN 2003 FMI 31, you can ensure optimal performance and efficiency of your Allison transmission system.

Allison Transmission Fault Code Spn 2003 Fmi 31 : Troubleshooting Tips. - Survival Savior (2024)


What is source address 3 fault code spn 2003? ›

This fault code is a data communication related fault indicating a loss of communication between your transmission control module and your engine control module. Be sure to check all your fuses and relays as well as verify all your power and grounds to your modules between your battery box and control modules.

What is SPN 2011 FMI 9? ›

SPN 2011/FMI 9

This diagnostic is typically the J1939 Message is Missing from Source Address 11 (dec) . This code sets when there is a loss of communication from the ABS module.

What is the spn 2003 fmi 14? ›

The fault SPN 2003 FMI 14 means there is a communication fault with the transmission. They are hard to diagnose because it is typically a wiring problem with no real definition of which wire is giving the fault.

What does SPN stand for in fault codes? ›

A Suspect Parameter Number (SPN) is a specific code used in the automotive industry to identify and diagnose faults codes in electronic control units (ECUs) within vehicles.

What is the active fault code? ›

Active fault codes mean the there is a present issue. In some cases, and in some engine models you can actually clear certain active codes. For instance, certain Volvo and Mack trucks will display active codes on the dashboard but when you plug in the diagnostic software the fault codes display as inactive.

What does FMI mean on a diesel? ›

FAILURE MODE IDENTIFIERS (FMI) Now that we have defined MID (The component) and PID (types of data), we can talk about Failure Mode Identifiers (FMI). Every diagnostic trouble code (DTC) that you find will have an FMI.

What is SPN and FMI? ›

For example, if you had a SPN 1791 code, it would point to a fault detected in the EGR Valve Control Circuit. FMI stands for Failure Mode Indicator which tells you the reason the fault code was set.

What does FMI stand for codes? ›

Page 1. Failure Mode Identifier (FMI) Codes on J1939 data link. The FMI is used along with the SPN to provide specific information that relates to a diagnostic trouble code (DTC). The FMI may indicate that a problem with an electronic circuit or an electronic component has been detected.

What is engine code FMI 31? ›

The SPN 23 FMI 31 code indicates that the engine is not receiving the proper amount of fuel. This can be caused by a variety of issues, including a clogged fuel filter, a faulty fuel pump, or a problem with the fuel injectors.

How do I reset the SPN? ›

Reset an SPN

To change the default SPN settings, open a command prompt and type the setspn -r hostname command. In this command, hostname should be replaced with the actual host name of the computer object whose settings you want to change.

How do I check my SPN? ›

Resolution. To check the SPNs that are registered for a specific computer using that computer, you can run the following commands from a command prompt: setspn -L hostname - Substitute the actual hostname for the computer for hostname(to see the hostname, type hostname as a command prompt).

What is the code 2003 on a Freightliner? ›

Here is the meaning of the fault code you have : SPN 2003 19 -Missing Transmission CAN Message -Received network data in error The transmission ECU must not be powering up ! This would explain why it won't even crank . There needs to be a neutral signal in order to allow the starter to crank .

What is fault code spn 171 fmi 3? ›

This fault code is for your ambient temperature sensor circuit. You either have a problem with the wiring harness for that sensor or a failed sensor is most likely the cause. Follow the troubleshooting information below in order to isolate your problem. Ambient Temperature input is shorted high or open.

What is SPN 3363 code? ›

Your code spn 3363 is short or failed DEF tank heater. This is a normal failure for the tank heater to fail.

What is a passive fault code? ›

Passive faults are DTCs that can be cleared after reading the trouble codes without changing vehicle parts.

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