What Does Code P0191 Mean on 6.7L Cummins? (How to Fix It)

The codes used by a Dodge Cummins Onboard Diagnostics or OBD system to identify an issue or problem in the vehicle are known as Diagnostic Trouble Codes. Different diagnostic trouble codes or DTCs represent different types of malfunctions in the car.

The P0191 code on Dodge Cummins indicates a possible inconsistency in the fuel rail pressure data. A variety of problems can cause this issue. A common reason is a malfunctioning fuel pressure sensor or a faulty fuel pressure sensor circuit.

Now you might be thinking about what to do if this code appears, don’t worry; by reading this write up you’ll get a broad insight into what this code means, its causes, symptoms, fixes, and other information

What Does P0191 Code Mean On 6.7L Cummins?

As mentioned before, the code P0191 on a Dodge Cummins indicates that there’s an inconsistency or anomaly in the fuel rail pressure data. Let’s break down the code to understand what it actually means.

  • P = Powertrain, the components that make your car move (In this case, the transmission)
  • 0 = A generic numerical taken from the SAE standard
  • 1 = Fuel and air metering
  • 91 = Specific fault index (In this case, it is denoting inconsistency in the fuel rail pressure data)

In easy words, due to an electrical or mechanical malfunction, the value expected by the PCM is not matching the signal received by the fuel rail pressure sensor.

How Serious Is P0191 Code On 6.7L Dodge Cummins?

The P0191 code on Dodge Cummins is considered to be critical. It will cause drivability issues and might cause the vehicle to jerk mid-driving state.

This issue may also lead to higher gasoline usage which can have a toll on your wallet. This issue is pretty serious and should be taken under consideration for diagnosis and repair.

What Causes P0191 Code On 6.7L Dodge Cummins?

There are several factors that contribute to this problem. The following are some of them:

  • Having Excessive or insufficient fuel pressure.
  • Having problems with PCM. For example, outdated software needs an update.
  • Faulty fuel pressure sensor.
  • Connectivity problem in the fuel pressure sensor.
  • Malfunctioning fuel pressure sensor circuit.
  • Failure of the fuel pressure regulator

How To Fix P0191 Code On 6.7L Dodge Cummins?

It is highly recommended to visit a service station for such an issue unless you have expertise in auto repair. To fix this code on a Dodge Cummins, the steps that have to be followed are as follows.

Step-1: Extract the Freeze Frame Data

The data or parameters collected in memory when DTC or Diagnostic Trouble Code is set is known as freeze frame data. This information basically represents the conditions present while setting the code. By using an OBD-II scanner, this data can be retrieved.

Step-2: Test Drive

Next, you have to go for a test drive to examine if the fuel pressure indication or reading is natural. This will help to get a better sense of what’s going on inside.

Step-3: Check Detector and Fuel Pressure

After taking your car for a test drive, you’ll have to check what exactly is the problem. Using a fuel pressure tester, it has to be checked whether it is a detector issue or a fuel pressure malfunction.

Step-4: Check the Connections of Wires

If the fuel pressure is normal, the next thing you’ll have to do is to use an oscilloscope to check if the connections and wire of the fuel rail pressure sensor’s circuit are unharmed.

However, if by any chance they are harmed or damaged, it should be replaced or fixed by an expert.

Step-5: Check Sensor

If the wire to the sensor’s circuit is not damaged and the fuel pressure is fine, then it is a problem with a malfunctioning fuel rail pressure sensor.

A Dodge Cummins runs at a very high pressure ranging between 5,000psi up to almost 30,000psi which is why this sensor plays a very critical role for the engine control module to function properly. If it is malfunctioning, it might have to be replaced.

To replace the sensor, find your way to the electric connector above the sensor in the rail and detach it. Then using a 27mm socket, loosen the sensor and slowly remove it. Place the new sensor properly with your hands.

Finally use a torque wrench and torque it down and reconnect the electric connector again.

Other Symptoms Of Getting P0191 Code On Dodge Cummins

The following are the common symptoms of the P0191 code on Dodge Cummins:

  • Engine stall or jerk
  • Increase in fuel consumption
  • Tailpipes have an odd smell
  • Triggers and flashing lights of engine inspection

How Much Does it Cost to Fix Dodge Cummins P0191 Code?

The cost for fixing the P0191 code will vary on what the actual problem is. Since it’s usually the fuel rail pressure sensor, according to the make and model, the cost for the part itself would range from around $90 to $250, if it is done by yourself.

However, if you take it to the service centers, the labor cost will add around $60 to $100. Keep in mind these service charges vary according to where the truck is taken and the amount of work done.

Can You Drive Your Dodge Cummins With Code P0191?

You will not be able to drive for long with this code since the vehicle will stall, jerk, or hesitate while driving. It is not recommended at all to drive with this issue.

In some cases, the truck will face difficulty to accelerate and even start due to a decrease in fuel supply to the engine. So it is crucial that you take the truck to a service center as soon as possible.

Conclusion

Like every other vehicle, Dodge Cummins can also have Diagnostic Trouble Codes or DTCs. If you ever face Code P0191, hopefully with the help of this article. you can diagnose and potentially fix it.

But if it seems too time-consuming and troublesome, you can always take it to a professional to get it done properly in exchange for some money.  Till then, have a safe driving experience.

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