What Is Fault Code SPN 5444 FMI 1? (Paccar, Freightliner)

With over 50,000 SPN codes, it stands to reason that there is at least one that watches over your oil supply. But do not be surprised if a code for oil shows up with codes for other components in your engine. In the end, it may not be a tough fix.

The SPN 5444 FMI 1 code stands for- Engine Crankcase Breather Oil Separator Speed Too Low. This code also indicates the following problem- Engine Crankcase Breather Oil Separator Speed Data Valid But Below Normal Operational Range - Most Severe Level; Engine Crankcase Ventilation Oil Spinner Speed Sensor

To learn more about this code, just continue to read our article. It has the information you want to know about so you can take care of this problem right away. The key words to motivate you will be ‘most severe’. You may experience performance issues as well.

Paccar SPN 5444 FMI 1


We have a copy of Paccar’s fault codes and there are several different codes that refer to the crankcase. The problem with this list is that it does not provide corresponding SPN FMi codes for each of their fault codes as Cummins does.

We do know that the company is very secretive about its codes and what they mean but this list removes a lot of the mystery behind them. The Paccar code for this problem could be P1529 or P153 B or P153C. We can’t be sure as the descriptions are not very clear.

The SPN FMI part of the code stands for - Fault Code Sets When the Engine Oil Separator Speed is less than 3,000 rpm for 45 Seconds. What creates the problem are the following conditions:

- Engine Coolant Temperature Greater than 65°C (149°F),

- Engine Oil Temperature Greater than 65°C (149°F),

- Engine rpm Greater than 900 rpm,

- Ambient Temperature Greater than -8°C (17.6°F),

- Barometric Pressure Greater than 10.9 psi (755 mbar)

Since Paccar is very protective of its information and repairs, we cannot offer you much more than this information. The best thing to do is call Paccar and see what they say.

Freightliner SPN 5444 FMI 1


Freightliner, on the other hand, is much more open and informative of this code, and the same reason as well as the source we placed in the last section applies here.

The repair sequence has up to 11 steps and you will be turning your ignition on and then off several times throughout the procedure. What you are going to find is that this code comes with 2 GHG numbers right after the FMI code. Those numbers are 14 and 17.

The repairs are the same and you can see the steps for both code situations at this link. What you have to watch out for is if there is any oil leaking or present. If so, then you will have to replace the breather.

If there is no leak or you replaced the breather, and the code still presents itself, then you may have damaged pins somewhere. That would be step 3 in the repair procedure.

You got to keep going till you find the source of the problem and make the right repair.

Detroit SPN 5444 FMI 1


While the above information will work for this engine brand, the problem may not totally be in the crankcase breather. Why we say this is because you may have other fault codes that will be set at the same time and those codes will lead you to different parts but are still connected with the crankcase breather.

In one case, the codes 459520 spn, 4333 (it is possible it is 4334 instead of 4333) spn, also presented themselves with this code. The problem component turned out to be the air pressure limiting valve between the DEF tank and the DPF.

Once that was fixed, the code was cleared. This was after the owner replaced all the filters not just the 3 in the engine. It may be wise to replace the breather at this time as well if it is starting to go bad on you.

SPN 5444 FMI 18


First, the bad news. We did not find this code on the official SPN code list nor did it appear on the complete Cummins fault code list. Then, nothing turned up in our searches for this code.

The good news is, you can still get an idea of what this code is telling you by looking at different portions of the code. SPN 5444 is Engine Crankcase Breather Oil Separator Speed Too Low.

So you know there is a problem in the crankcase breather area of your truck. FMI code 18 stands for- Data valid but below normal operating range - moderately severe level.

The words moderately severe should have you taking your vehicle to the nearest best and most qualified mechanic you trust. Unfortunately, that is the best advice we can give as no data sheet has appeared explaining the repair steps or the source for this code.

Sometimes we can find the codes mentioned on discussion forums but that was a dead end as well for this specific code. We doubled check to see if SPN 5443 FMI 16 was related to this code but it was for Dpf Hc Absorption High.

All the 5443 codes were for that component and not related to the crankcase breather.

Some Final Words

Sometimes tracking down codes can be very frustrating. Not every code is documented as well as it should be or they are dealer-level diagnostic codes only.

We cannot rule that option out and as we said earlier, the best thing to do is talk to a good mechanic or your dealer to see if they can track the code down for you when they do not appear on data sheets or code lists.

The repair for the breather does seem simple enough once you get to the problem.

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