How to Fix P1223 Code On Cummins? (Completely Explained)

If you’ve been driving a Cummins truck for a few years, you’ve probably dealt with a variety of DTCs (Diagnostic Trouble Codes). Though this can bother you sometimes, it helps the driver discover your car’s issues and can help you fix them.

Code P1223 on Cummins refers to the problem of leak detection according to the quantity balance. When an excessive flow of fuel leaks inside of the fuel system, then it causes Code P1223. 

If you’re driving and this code P1223 pops up on your Cummins, then not knowing the actual cause of the code can bother you. Therefore, let’s show you all how you can find out the reason behind this code and fix it immediately.

P1223 Code On Cummins

What Does P1223 Code Mean On Cummins?

The code P1223 is a Diagnostic Trouble Code or DTC. This particular code means the issue of leak detection according to the quantity balance. The ECM, which stands for Engine Control Module, detects leakage when the flow of the engine’s fuel exceeds an anticipated number.

To keep your engine system stable, there is a fuel amount required by the engine’s fuel system. Here, the requirement for fuel amount relies on the injection quantity, fuel pressure, coolant temperature, and engine speed.

However, when the fuel flow exceeds a specific value, the ECM-Engine Control Module turns on the leakage detection code P1223. And when the code is detected, the system initiates a counteraction. Now, let’s breakdown the code P1223:

  • P = Powertrain, vehicle-moving forward system.
  • 1 = Universal Generic Code for SAE.
  • 2 = Affected Sensor Number
  • 23 = Specific trouble sign (Here, the leakage detection)

How Serious Is The P1223 Cummins Code?

When discussing the severity of this trouble code, let us warn you that this specific code is a severe one for your vehicle. You should not continue using your car in any situation after the appearance of this code.

Because your car’s performance won’t be the same, it may also create other problems like the vehicle keeps shutting off, the engine not turning on, etc. Therefore, a counteraction is initiated by going to a specific value in that situation. Then, a fault will be set on your vehicle to enable the engine.

However, if the vehicle or engine can’t detect the leak under the count of the counteraction, your Cummins engine will return to its normal condition. If it doesn’t reach zero, your vehicle will remain in trouble.

What Causes The P1223 Code On Cummins?

There are several reasons which can cause the P1223 Code on Cummins. As we’ve already mentioned the major one earlier, let’s discuss some other causes of the P1223 code on Cummins:

  • Worn out fuel injectors
  • A lazy and troublesome regulator
  • Contamination of fuel
  • Damaged injection pump
  • Leakage in high-pressure relief valve

How To Fix The P1223 Code On Cummins?

Fixing trouble code P1223 can give anyone a hard time. Even if you’re a professional, you’ll still need a few hours to fix this. Therefore, no one should attempt to fix this code on their own.

However, if you have had your fair share of time dealing with  automobiles, then you can certainly give it a try by following the steps given below:

Step 1: Diagnosis

First, turn the ignition on. Then, get an OBD-II trouble code reader and diagnose the code P1223 on your Cummins. Once you’ve diagnosed the reading of this code on your reader, you can move on to the next steps.

Step 2: Scanning for Other DTCs

Now, you need to start scanning the other Cummins module using the same scanner. This scanning will help you determine if any other trouble codes are available. If you don’t find any other DTC in your system, then you need to get down and manually inspect the parts.

Step 3: Fixing Other DTCs

But if you find other DTCs, you need to deal with them first. Once you fix the other trouble codes, you can start fixing the one at hand.

Step 4: Fixing

There is a point where your engine may feel slow. These are known as the low-PSI points. As the engine detects fuel leaking in the system, the stock injectors, clogged fuel filter, limit valve, low fuel supply, faulty lift pump, etc., are the parts through which the fuel can leak.

● Testing

To identify the source of the leak, you need to try a basic fuel test called “fuel test delivery.” First, disconnect the fuel supply line to your engine’s injection pump. Then try to bump the starter. The instruction manual spec tells that it should be 500ml per 30 seconds.

If the number remains within the given spec, your engine has a problem elsewhere. Hence, you need to perform another test, which is injector return. Now you’ll require special tools for this test, so it would be better if you get a Cummins authorized or Dodge dealership repair shop to do this test.

● Identifying

From this test, you’ll be sure about the leaking injector. It can also occur because of loose tubes or faulty valves. This result can identify them also. So, now all you’ve to do is just replace the leaking part, and your trouble will be soon over.

Step 5: Replacement

As you’ve already sorted out the problem, now it’s time for the replacement of the damaged or worn out part. It can also be repaired if the condition of the part is repairable. But if that’s not the case, then replacement is undoubtedly the best option.

Step 6: Control Module System Check

You need not follow this step to complete the fix process. A control module system check is a regular maintenance check to find out the trouble or issue of any Cummins vehicle.

Other Symptoms Of Getting P1223 Code On Cummins

Suppose the trouble code P1223 has already appeared on your Cummins. In that case, there will be symptoms like the engine getting shut off repeatedly, the engine not turning on, etc., but apart from these two symptoms, some other signs of getting the P1223 code on Cummins are as follows:

  • Engine Misfiring
  • Mechanism over-pressurized
  • Dash binger keeps going off
  • The half-powered engine in the Limp Mode
  • Repeatedly illuminating heater lights

How Much Does It Cost To Fix The Cummins P1223 Code?

It is hard to say the exact amount to fix the Cummins P1223 code because the cost varies from city to city and shop to shop. Even the rate of hourly work is different from place to place. But most professional automobile repairers charge a fixed hourly rate to fix trouble codes like P1223 on Cummins.

Fix Cummins P1223 code; it may take one or two hours of professional work. The charge will be between $80 and $160 per hour. So, you can fix trouble code P1223 for this cost, including all fees.

Can You Drive Your Cummins With Code P1223?

You can drive your Cummins with code P1223, but we won’t like to recommend that to you. Because when the fuel overreaches back to the ECM, your Cummins may start showing this trouble code P1223. It is unsafe to drive with the code appearing on the Cummins screen.

Because your Cummins may stop in the middle of the road or not start, this is quite risky for any driver driving a Cummins. This is why you should not drive your Cummins with a P1223 code. 


In this article, we have discussed the basics of understanding the P1223 code and show you the precise ways to fix this problem. The P1223 code is a severe DTC that can harm your vehicle’s engine and performance.

So, it would be wise to fix the car right away when this code appears. You’ve already seen that the fixing process is not so difficult.

With precision and experience, anyone handling an automobile for years can solve this issue in no time. Therefore, you should not worry when this code appears, but rather try to follow the guidelines to fix your car in no time.

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