What Is SPN 95 FMI 16 Cummins? (FMI 15, 18)

It can happen to you. That is one thing about these error codes, they do not discriminate. All error codes will react to the same situation no matter what type of RV coach you own. The key is to make sure the mechanic you go to knows what the code refers to.

This error code is “Fuel Filter Differential Pressure - Data Valid But Above Normal, Operating Range - Moderately Severe Level. Every possibility has to do with your fuel delivery in some way. Even with this knowledge, some mechanics do not know what is causing it.

To learn more about this code and what it refers to, just continue to read our article. It has the information you want to know about so you can deal with this issue before it becomes a major problem.

SPN 95 FMI 16 Cummins

Here are the possibilities that come with this error code:

1 Engine will not start

2 Low-pressure fuel system component is malfunctioning

2.1 Fuel Inlet Restriction check

2.2 Air in fuel check

2.3 Fuel filter differential and gear pump pressure check

3 Fuel injector return flow check

3.1 Fuel injector isolation test

4 Fuel pressure relief valve return flow excessive

5 Air in fuel check

6 Damaged fuel supply lines

At least those are a good place to start. This link takes you to all the details of each possibility and what to do to solve them.

Cummins SPN 95 FMI 15

This code has the same possibilities as the previous one but there is a slight difference between the two codes. “Fuel Filter Differential Pressure - Data Valid But Above Normal Operating Range - Least Severe Level.

The keyword is in bold. When you see this code, you can rest a little easier as it is not as damaging as the 16 code. But you should check out the parts involved and stop any problem from getting worse.

All the details are at this link.

SPN 95 FMI 18 Cummins


We did not find a listing for this specific code. But we will present the SPN 94 FMI 18 code because it also has to do with the fuel delivery system. This code means “Engine fuel delivery pressure- Data valid but below normal operating range- moderately severe level.

No warning light will be illuminated when you see this code. What would be nice is if the different engine makers used the same codes and listed every one of them in a table somewhere.

SPN 95 FMI 7

The SPN 95 code deals with your fuel system and the FMi codes provide a little more detail about the general error code that has been triggered. 

According to that list, #7 refers to “Mechanical system not responding properly” which would be just about anywhere on your fuel line. If you look at the SPN 95 possibilities listed above, you should get a general idea of where the problem is in the fuel system

SPN 95 FMI 2


With over 50,000 SPN codes and about 21 FMI codes, not everyone will show up on all the lists. As you know by now SPN 95 refers to a fuel problem. The common definition for the FMI 2 code is “Data erratic, intermittent, or incorrect “

For this one, you may need the help of a trained mechanic to see what it is referring to. There could be a loose connection somewhere, a broken wire, or some other problem that relates to reporting any data to the ECM, etc.

SPN 95 FMI 0

One of the reasons why no one can find these fault codes is that no one is talking about them. They may not deem it important enough or they may not have seen one on their dash etc., or they know what it is.

The common definition for the FMI 0 code is “Data valid but above normal operational range (that is, engine overheating)” That is pretty straight forward.

SPN 95 FMI 3

SPN-95-FMI-2 (2)

While there was not an SPN 95 FMI 3 code listed, there was an SPN 96 FMI3 code which seems to be about the same. Here is what the latter number means:

This code is most likely due to either fuel tank wiring or the fuel sending unit inside the fuel tank being faulty. Inspect wiring for cracks or breaks and perform a resistance check on the sensor. The sensor resistance range is 6-90 ohms +- 1 ohm. 90 Ohms is a full tank and 6 Ohms in an empty tank.”

SPN 95 FMI 4

This code is the opposite of the FMI 3 error code. It says “Voltage below normal or shorted low” However we didn’t find any alternative code as we did for the previous option.

Cummins Fuel Filter Differential Pressure


This is a common technique used by many engine makers to monitor the flow of fuel or other particulates. When it comes to fuel, you can see your fuel pressure at different points of engine operation.

At idle you may see 10 to 15 psi but if you get up to 2500 and the fuel pressure is under 10 and close to 0 then you know you have a fuel pressure problem. Generally, you may need a trained mechanic to sort this problem out.

There are different parts available and for a Cummins engine, you could be paying about $250 for a new one.

Some Final Words

Unfortunately, no one is keeping an accurate record of all the various SPN and FMI codes. One detailed code sheet we came across only had 4 FMI codes for SPN 95. Only 2 were for the ones in the above list.

If you see a code that you do not understand or have never seen before it is best to go to a mechanic or your dealer to find out what the problem is. Information is sparse right now.

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