What Is SPN 157? (Cummins SPN 157 FMI 18 Explained)
With all the modern technological equipment on car and truck engines these days, it can be confusing when different error codes pop up on your screens. Engines are not simple anymore. It may take a master’s degree in automotive technology to figure out what those codes mean.
This code means- Injector Metering Rail 1 Pressure - Data Valid But Below Normal Operating Range - Moderately Severe Level (source). To properly diagnose and understand the code, you will need the Cummins electronic service tool or its equivalent.
To learn more about this code, just continue to read our article. It explores the topic so you have the right information to handle the problem. take a few minutes to see how this important information can help you solve your engine woes.
What is Cummins SPN 157 FMI 18?
The definition has been given above and the source has all the instructions to follow to help remedy the situation and get your vehicle back on the road and operating normally. To do this yourself you will need the proper code scanner and reader. Plus, you do have to deal with more than just this fault code.
According to those instructions you also have to “Before troubleshooting this fault code, troubleshoot any fault code that is active or has more than one inactive count
within the last 25 engine operating hours from the following list:
- Fuel: 271, 272, 281, 449, 451, 452, 484, 553, 1911, 2311, 2343, 2372, 3727, 4691, 4726, 5585
- Voltage: 1117
- Sensor supply 6: 515, 516”
There are about 11 more pages of instructions to follow when your truck or car will not start. Also according to that manual, you have 12 more possibilities to check before you are done. Unless you get the source quickly and then you can stop your work.
If you are not mechanically inclined, it would be best to talk to a dealer or professional mechanic as they have spent a lot of time learning these codes and what needs to be repaired.
The instructions and the process may be too confusing for most amateur mechanics to handle. But you are the judge of your mechanical abilities and make sure you know your limits as you could damage other components in your work.
Cummins SPN 157 FMI 18?
We gave you one meaning to this code but like most error codes, there is more than one meaning behind the letters and numbers. Here are three more possibilities related to this code.
- Fuel Rail Pressure High
- Fuel Rail Pressure Too High
- Fuel Rail Pressure Too High: Engine Injector Metering Rail 1 Pressure Data Valid But Below Normal Operating Range - Moderately Severe Level; Pressure Deviation Too Low (source)
Then also like other error codes, you should not delay in getting this one checked out. There is a possibility of other components being damaged if you let it go for too long. If you are on the road, you should have time to wait till you get to your next stop unless you just started on your journey.
No matter the brand of your truck, RV, or car, if you have a Cummins engine, you should go to an authorized Cummins dealer or repair facility. Let the professionals handle this code as it may be beyond your mechanical expertise.
Even if your plungers are made of titanium, there is always a chance of failure, and not just on rare occasions.
Injector Metering Rail 1 Pressure
According to one mechanic, per one owner’s story, this is the toughest code to fix. According to that owner’s story, it takes several weeks to figure out what is wrong. The reason for this is that Cummins has created a special checklist for this error code.
Then Cummins monitors the mechanics as they go through this checklist. What that means is that the mechanic has to go through each step and take no shortcuts. On top of that, it takes special equipment to diagnose this error code.
Not every authorized Cummins repair shop close to you has this special equipment or the special tools to fix the problem. What caused this problem in this particular case was a drop in fuel pressure. Sometimes the only fix is replacing the fuel tank.
In another case, found that once the tank was removed and opened up, a small piece of plastic was found inside the fuel tank that impeded the flow of the fuel. That triggered the alert and caused a long repair time.
Finding The Problem
It has been said that there is a big difference between a Cummins shop and an authorized dealer. The reason this has been stated is that the former has the specialized tools and equipment to diagnose the problem. The latter is helpful but often lacks those tools and knowledge.
One owner said this about his similar problem-- “that took 3 repair visits and a total of 4 weeks and many hundreds of miles driving back and forth to repair places. My problem was resolved only when we went through three different shops, 3 sets of local mechanics, the field supervisor, the regional service supervisor, the lowest of three Cummins engineering levels, and finally the middle Cummins engineering levels.” (source- Gary.Jones post).
Some Final Words
Not all error codes will be easy to fix. They may not be easy to find either as you just found out. Fortunately for the two owners, the companies they bought their RVs from were very helpful.
This is not a DIY fix. You will have to go to Cummins or their chops to get the problem resolved. Even if it is something simple like plastic in the fuel tank, it may take some time to find the problem. Roadside emergency service companies can be very helpful at this time.
