How to Fix P0251 Code On Dodge Cummins? (Fully Explained)

DTCs or Diagnostic Trouble Codes are a part of a diesel truck, and your Dodge Cummins is no exception. They’re like a warning sign that something is wrong with your engine, and needs to be solved.

The P0251 Dodge Cummins codes indicates Malfunction of Injection Pump Fuel Metering Control “A”, and it’s a common error mostly triggered by a flawed FRP sensor.

If you want to know more about what the P0251 code means on Dodge Cummins, we’ve got you covered. We’ll cover everything you need to know about this error code–the symptoms, causes, troubleshooting options, and associated costs throughout this article.

P0251 Code On Dodge Cummins

What Does P0251 Dodge Cummins Code Mean ?

The P0251 is a generic fault code on Dodge Cummins or any OBD-II equipped diesel-fueled vehicle. This code means your truck’s injection pump fuel metering control circuit ‘A’ is malfunctioning.

The injection pump is what pressurizes the fuel into the cylinder. Proper injection requires accurate pressure and timing. Your vehicle’s engine control module uses the FRP sensor to monitor the pressure in the fuel rail. If there’s a fault in the sensor, for instance, a pressure drop, the PCM sets the P0251 code.

Here’s a breakdown of what the code has to do with this problem.

  • P = Powertrain, the system of components that propels your car forward
  • 0 = a generic number derived from the SAE standard
  • 2 = Fuel and air metering
  • 51 = Specific fault index (In our case, this denotes injection pump fuel metering control circuit ‘A’)

How Serious Is P0251 Code on Dodge Cummins?

The P0251 isn’t that severe since it’s an electric failure. However, it can still cause expensive repairs if left unchecked for extended periods. Injectors are a crucial part of the combustion process and need to be working correctly for your truck to run efficiently.

Usually, the code results from a failed FRP sensor. In that scenario, it can cause your vehicle to enter limp mode, limiting the amount of power your engine produces. This is to prevent any further damage from occurring. So while the P0251 code isn’t serious, it’s still important to get it fixed as soon as possible.

What Are the Symptoms of the P0251 Code on Dodge Cummins?

The most common symptom of the P0251 code is an illuminated Check Engine Light coupled with a decrease in fuel economy. Other than that, you might also experience:

  • Slow or hard starts
  • Rough idling
  • Hesitation during acceleration
  • Smoke emissions from the tailpipe

What Causes P0251 Code on Dodge Cummins?

As mentioned earlier, the most common cause of the P0251 code is a fault within the FRP sensor. The sensor may have its signal circuit open, short to voltage, or short to ground. A complete failure of the FRP system is also possible, although it’s very rare. There are also other possibilities. like-

  • Bad, contaminated, or incorrect gasoline
  • The optical sensor is dirty
  • Clogged fuel pumps, filters, or injectors
  • Malfunctioning intake air temperature sensors, accelerator pedal position sensors, or crankshaft position sensors
  • The wiring related to the above sensors is shorted to power or ground
  • Corrosions on the above sensors
  • Fuel control actuator failure
  • Injector leak

How To Fix P0251 Dodge Cummins Code?

The best way to fix the P0251 code is to take your truck to a certified mechanic or dealership. They will have the right tools and experience needed to correctly diagnose and fix the problem. Yet, if you want to attempt a DIY fix, here are some troubleshooting steps you can follow.

Step 1: Check for Any Visible Leaks

You begin with the basics before moving on to the advanced steps. The first step is to check for any visible fuel leaks. If you see any, fix them immediately by replacing the O-rings or seals.

Step 2: Clean the Optical Sensor, Fuel Pumps, Filters, and Injector

If the optical sensor is dirty, it can cause the P0251 code. Clean it with a cloth or compressed air and see if that solves the problem. You should also check the fuel pumps, filters, and injectors for blockages or contamination. Clean them if necessary.

Step 3: Flush and Refill the Fuel Tank

If the problem persists, flush and refill the fuel tank with the correct gasoline suggested by the manufacturer. This will eliminate any bad gas that might be causing the P0251 code.

Step 4: Check All The Wiring And Sensors

Next, check all the wiring and sensors related to the injection system. Ensure there aren’t any loose connections and that all the sensors are functioning correctly.

Step 5: Test The Fuel Pressure

When the steps above don’t fix the P0251 code, the next thing you should do is test the fuel pressure. Low fuel pressure can cause the code to trigger. Use a fuel pressure gauge to test the pressure and compare it to the manufacturer’s specifications.

You may have a clogged fuel filter or a faulty fuel pump when the fuel pressure is low. Clean or replace them if necessary.

Step 6: Inspect The FRP Sensor

If you find the fuel pressure is okay, it’s time to inspect the FRP sensor. Start by disconnecting the sensor’s electrical connector and then removing it from its mounting bracket.

Check the sensor for any physical damage, such as cracks or breaks. If you find any, replace the sensor. If the sensor looks okay, clean the optical lens with brake cleaner and then reconnect it.

Step 7: Check The Wiring Harness

If the FRP sensor has no visible damage, check the wiring harness for any damaged, frayed, or loose wires. If you find any, repair or replace them as needed.

Step 8: Test The FRP Sensor

Once you’ve fixed or replaced all the damaged components, the next step is to test the FRP sensor. To do this, you’ll need a multimeter.

First, connect the multimeter to the sensor’s signal wire and ground the other lead on the engine block. With the multimeter set to Ohms, crank the engine.

The reading should fluctuate between 0.5 and 4.5 volts. If it doesn’t, you’ll have to replace the FRP sensor.

Step 9: Check the Fuel Control Actuator

If the FRP sensor checks out, the last thing you can do is to check the fuel control actuator. This component controls the amount of fuel that’s injected into the cylinders.

To test it, you’ll need a vacuum pump. First, connect the vacuum pump to the actuator’s inlet port and turn it on.

Check the voltage on the actuator’s signal wire with the pump running. It should be between 4.5 and 5 volts. If it’s not, replace the actuator.

How Much Does It Cost To Fix Dodge Cummins P0251 Code?

The P0251 code doesn’t require costly repairs. And doing the repairs yourself will save you a lot more. It all depends on the issue. For example, if you just need to clean the optical sensor or the clogged filters, it shouldn’t cost more than $50.

However, if the problem requires replacing the FRP sensor, it could cost more than $100. And if you have to replace the fuel control actuator, it could cost upwards of $150. Labor costs should be around $80-$100.

Can You Drive Your Dodge Cummins With code P0251?

Driving your Dodge Cummins with the P0251 code won’t danger you or your passengers. Yet, it could hamper your experience with intermittent misfires or stalling if left unchecked for an extended period. Besides, you won’t be able to legally pass inspection with the check light on.


We hope this article was helpful whether you were just looking for basic information or wanted more information on how to fix the P0251 on Dodge Cummins diesel trucks.

As you’ve seen, it’s barely the end of your truck when it has the P0251 code; neither will the repairs cost you a fortune.

You can diagnose and fix the problem yourself with a little time and effort without spending hefty money. Just make sure to follow all the steps in this article carefully, and you’ll be back on the road in no time.

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