What Is Fault Code SPN 3359 FMI 31? (Allison Transmission) (2024)

Once those amber and red lights get illuminated on your dash, you need to get more information. That is what the SPN FMI code system is all about. Unfortunately, some of these codes just do not bring the information you need.

You are not going to like the meaning of this code. The official SPN FMI list simply says - Transmission Service (filter Life Monitor). The FMI portion of the code will only state, a condition exists. Which is information you already know about.

To learn more about this code and similar ones related to SPN 3359, just continue to read our article. It explores these codes to give you the best information possible and save you search time. Getting you back on the road quickly is one of our goals.

Code SPN 3359

Allison Transmission SPN 3359 FMI 18

Allison Fault Code SPN 3359 FMI 31

What Is Fault Code SPN 3359 FMI 31? (Allison Transmission) (1)

What happens when you see this code illuminated on your dash along with the check transmission light is you are going on a treasure hunt. Unfortunately, this hunt doe not bring a nice monetary reward.

Instead, it will lead you to a possible source of the problem. This Allison code is very generic and does not tell you anything you do not already know. The only clue you have is the words in brackets- Transmission Service (filter Life Monitor).

However, in this particular case, it may not be the transmission filter that is the problem. It may be a bad connector which is what happened to one owner. His story is long but one shop said the transmission was missing a wire which is almost unheard of.

The real source for this code popping up on his dash was that there was a broken pin connector that would not connect to the #80 connector in the transmission.

If the first diagnosis does not sound right, it probably isn’t or it may not be accurate. Until you do the search, you do not know where the problem lies when this code appears.

Also, this fix may or may not be under warranty and you would have to check with several companies associated with your RV to find out if it is or not. The cost of this repair at that time was $800.

Allison SPN 3359 FMI 1

What Is Fault Code SPN 3359 FMI 31? (Allison Transmission) (2)

There are codes that are very straight forward and tell you exactly what is going on in your engine or transmission or other module systems. This is one of those codes.

Allison SPN 3359 FMI on the official code list only says- Transmission Filter Maintenance Required (p088b). But on one data sheet, it defines the code as- Transmission Filter Maintenance Required – Low-Most Severe (3).

We put the words in bold to make sure you caught that discrepancy. The reason for the discrepancy is that the FMI portion of the code refers to oil and not transmission fluid. This may not be an important distinction but we wanted you aware of this issue.

The numbers in the bracket for the first definition are the correct Allison fault code for this problem. The sheet we will link to later, says this fault code is telling you that you have a ‘very deteriorated filter.’

If that is the case, then we understand why the other data sheet, written for US army vehicles only, says this fault code is most severe. Most likely, when you see this code, you need to change the transmission filter as quickly as possible.

If you do not take care of it right away, you may suffer more severe damage to your engine or transmission.

Allison Transmission SPN 3359 FMI 18

What Is Fault Code SPN 3359 FMI 31? (Allison Transmission) (3)

According to one sheet of codes, this SPN FMI code may translate into Allison fault code Po88a. If that is correct, then that is the same information as SPN 3359 FMI 16 which also equals Alllison P088a.

On the official SPN fault code list the latter code states- Transmission Filter Maintenance Alert (p088a). P088a means- deteriorated filter. In other words, the problem is basically the same as P088b but not as severe.

You will need to change the transmission filter to get the code to disappear. This Allison code will appear on page 32 of the set of Allison codes we will link to in the next section.

Just so you know, there were no data sheets, no discussion forums, or other information popping up for either SPN 3359 FMI 18 & FMI 16. The best we can say is that if you have doubts about this code, talk to your local Allison repair shop to get more accurate information and repair steps.

This is not a code that you want to drive 500 or even 100 miles when it is illuminated. You can drive locally to the repair shop but long distance is out of the question.

Some Final Words

While some codes are not very informative, others point you to the exact problem you need to deal with. Unfortunately, you never know which is which until you click on the fault code and see what it says in its explanation.

It is fortunate that the official SPN fault code list does place some of Allison’s fault codes in its explanations making finding the reason for the code easier. That link will also provide Allison’s contact information in case you have a problem that is not covered by that manual.

What Is Fault Code SPN 3359 FMI 31? (Allison Transmission) (2024)


What does FMI 31 mean? ›

SPN 521049/FMI 31

Description This Code Sets When There is a Code Present for the Diesel Exhaust Fluid (DEF) Tank Level, DEF Dosing Unit, DEF Pump, NOx Sensors, Blocked DEF Line, DEF Quality, NOx Efficiency, Selective Catalyst Reduction (SCR) Harness and/or SCR Sensor.

What is a transmission oil filter restriction switch? ›

An oil filter restriction sensor device for warning the operator of an internal combustion engine when the engine oil filter has become restricted and requires replacement comprising a sensor body and a threaded adapter for mounting the sensor body between the engine mounting bracket and an oil filter having a filter ...

How to clear Allison fault code? ›

Press and hold the MODE button for 10 seconds to clear both active and inactive codes. Sensor and Diagnostics operation of your Allison Automatic, and is not intended to replace your Operator's Manual.

What is the code for the Allison transmission filter? ›

Note: The most common diagnostic trouble code associated with the illumination of the CHECK TRANS light is DTC P088B-Transmission Filter Deterioration. If the CHECK TRANS light is going on without any apparent transmission concerns, please refer the customer to their closest Allison authorized repair location.

What does spn and fmi mean? ›

SPN stands for Suspected Parameter Number which tells you the circuit where the fault occurred. 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 is the FMI failure mode indicator? ›

Failure Mode Indication (FMI), as part of the J1939 standard used in heavy-duty vehicles, functions by closely monitoring system components. When a fault occurs, FMI generates a precise code that identifies the specific nature of the issue, much like an advanced version of a 'check engine' light.

Can a clogged transmission filter cause not to shift? ›

You may experience a delay or hesitation when shifting gears, and the transmission may seem to struggle to engage properly. Additionally, you might notice the engine revving without a corresponding increase in speed.

How do I know if my Allison transmission is bad? ›

If your Allison transmission takes a few seconds to respond after you've switched gears, something's wrong. Not only is this inconvenient, but it's also a potential safety hazard if you're unable to stop or start the vehicle in time. Have a professional examine the transmission immediately.

How do I reset my Allison push button transmission? ›

If the WRENCH ICON remains on or flashes, this indicates there is a service issue relating to clutch, filter or fluid life. For either a push button or bump lever shift selector, press and hold the MODE button for approximately 10 seconds while in Filter Life Monitor mode.

How many sensors is on a Allison Transmission? ›

Note: The Allison 1000 Series, 2000 Series, and 4000 Series transmissions have three external speed sensors: On the front lower passenger side: the Engine Speed Sensor.

Where do I find the transmission code? ›

You can find your transmission type on your window sticker, a Build Sheet, or a Vehicle Identification (VIN) Decode Letter.

What does FMI stand for codes? ›

FMI stands for failure mode identifier—this part of the fault code tells you what type of problem your truck has. For example, in the fault code SPN 3226 FMI 13, the SPN number 3226 tells you the problem is with the SCR outlet NOx sensor and FMI 13 tells you that the signal from the part is unavailable.

What does FMI mean in cars? ›

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 does FMI 13 mean? ›

The SPN 13 FMI 13 code is a diagnostic trouble code for a fault with the intake manifold pressure sensor. This code is set when the sensor signal is out of range or if the sensor is not functioning properly. The intake manifold pressure sensor is used to measure the pressure of the air in the intake manifold.

What is the code FMI 31 on a spn 4364 engine? ›

This fault code indicates that the nox emissions are not being reduced enough by the SCR catalyst. There are many possible causes for this fault code including: Degraded DEF fluid. A faulty SCR catalyst.

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