What Is The Cummins Fault Code SPN 3031 FMI 9? (Helpful Guide)

Do not be alarmed if you do not find this code on other lists you have checked. There are too many, along with the different FMI codes to include on every error code list. Kind of makes this a tough system to follow.

The SPN 3031 error or fault code stands for Aftertreatment 1 Diesel Exhaust Fluid Tank Temperature 1. But do not be surprised if you do not see it on the Cummins Fault Code lists. They have a different numbering system than SPN FMI does.

To learn more about this error code and how to fix it, just continue to read our article. It has the information you want to know about so you can find the problem and then the solution even quicker. Things are not as straight forward as they may seem.

What is Code SPN 3031?


This code, at least on the SPN list, is a stand-alone code. We did not see any other FMI numbers attached to it on the main list of error codes. Other numbers had up to 22 options attached to them.

3031 only has one option and it stands for Aftertreatment 1 Diesel Exhaust Fluid Tank Temperature 1. What this translates into is that the DEF tank is not reading the temperature it is supposed to be reading.

This may take a simple ECM update to cancel the error code. But for some reason, even though it does not have more than one explanation, this code could also stand for if there is a DEF heater valve stuck open, or there is a problem with the DEF tank sender or finally, it may indicate a problem with the DEF header.

If you are under warranty either contact Spartan or Cummins and the former can diagnose it over the phone or the Cummins repair shop can contact Spartan for you and get the right fix.

Cummins SPN 3031 FMI 9


We have not found an SPN 3031 or even a Cummins 3031 error code with the FMI 9 or any FMI number attached to it. Even the comprehensive list of SPN codes does not break it down into these sub-categories.

We have given you some indication of what the problem may be. But it also may be that the temperature sensor on your DEF tank is bad. The one 3031 error code that came with the SPN code is the next sub heading section and not this one.

The same issues in the previous section will apply to this error code. At least it will be a place to start. It is best to check with a dealer as the code sheets listed on the internet have all been incomplete.

Check the DEF tank’s header to see if that is the problem. The FMI code is not listed for this number at this time.

SPN 3031 FMI 3


The Vanderhaag website lists this error code on its Cummins Vehicle Diagnostic Report. Like all other lists, we found except the comprehensive SPN list, is not in numerical order.

The meaning of this FMI error code is “Aftertreatment 1 Diesel Exhaust Fluid (DEF) tank temperature sensor voltage above normal or short to high voltage.” Usually, it will trigger an Amber warning light on your dashboard.

What this seems to translate into is that the temperature sensor may be bad or you have a short in the system somewhere. It is best to take it to Cummins or contact Spartan to get the right part sent to you if you are still under warranty.

From all reports, Spartan seems to have great customer service and handles problems very quickly.

SPN 3031 FMI 2


This error code explanation came through a mechanic who posted a data sheet for this specific code because someone specifically asked about this code. What it means is:

Aftertreatment Diesel Exhaust Fluid Tank Temperature - Data

Erratic, Intermittent, or Incorrect. The diesel exhaust fluid tank

the temperature sensor has indicated a tank temperature is too high or

too low for the ambient conditions.”

The possible sources for this code are:

- “In-range failure of the diesel exhaust fluid tank temperature sensor

- Malfunctioning ambient air temperature sensor

- Damaged wiring harness

- Malfunctioning aftertreatment diesel exhaust fluid co”

You can read this data sheet at this link. This data sheet is from Cummins but it was originally published in 2008. This code may or may not still be in effect for newer engines.

We suggest talking to Cummins to see if any changes have been made over the past 15 years.

Cummins SPN 3031 FMI 18


This code may be accompanied by 2 other codes, spn 4342 - fmi 5 and spn 5246 - fmi 0 which puts the vehicle into a derate situation. This specific code means:

Aftertreatment Diesel Exhaust Fluid Tank Temperature - Data Valid But Below Normal Operating Range - Moderately Severe Level. The diesel exhaust fluid tank temperature is unable to reach its set point.

Diesel exhaust fluid injection into the aftertreatment system is disabled.”

The possible sources for this problem are:

- Blocked or restricted coolant flow to the diesel exhaust fluid tank heater

- Disconnected or broken tank heater coolant supply hose

- Malfunctioning or stuck closed diesel exhaust fluid tank heater control valve

- Malfunctioning or stuck aftertreatment diesel exhaust fluid tank temperature sensor

- Operation in extremely cold ambient conditions

You will need a mechanic to handle the problem.

Some Final Words

It takes some doing to find all the different meanings of these fault codes. For some reason, the lists of codes placed on the various websites are not all-inclusive and leave out pertinent details.

That means if you do not understand a code or cannot find it, contact a dealer or mechanic who has the complete list. While most of the 3031 error codes are not severe, the FMI 18 is and you need to be careful when seeing the different codes.

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