P0871 Dodge Cummins (Beginners Guide)

ByAllan

Traditionally, if you notice a fault with your vehicle’s performance and are convinced it is engine related, you face the dilemma of determining where the problem lies.

But, again, you’d have to depend on your experience or senses to make an accurate prediction. 

However, modern vehicles and engines have eliminated this stress with built-in diagnostic systems that use codes to communicate exact engine problems.

The Cummins engine of your Dodge also benefits from this upgrade. Let’s consider one such problem code in the Dodge, the P0871.

The P0871 Dodge Cummins signifies a fault that has to do with the transmission fluid pressure. Dodge is among the first brands to experiment with Cummins engines, and surprisingly, the outcome is what we see in the super performance of the Dodge vehicles, especially trucks. 

What Is P0871 Dodge Cummins?

P0871 is a kind of diagnostic problem code. Your Dodge Cummins’ ‘check engine light on’ shows the transmission; the transmission fluid pressure sensor “C” switch is faulty.

The code is generic, so don’t get it twisted: it is defined in the same way for every Dodge Cummins engine or other vehicles from the 1996 model year onwards.

The OBD-II generic code signifies too much or insufficient fluid pressure in the transmission.

Shortage in transmission fluid pressure results from a lack of transmission fluid.

The RFE Dodge kit is helpful in this system, but if transmission fluid leaks for any reason, then be sure of a problem since there will not be enough fluid levels for your car to perform properly.

I advise you to consider checking your Dodge Cummins’ transmission fluid a top priority, especially if you value your car and are safety conscious.

In addition, you should ensure to fill your transmission fluid to a remarkable amount and ensure it is without blemish.

Please understand that ‘Dodge Cummins’ as referred to in this context, can be any of Dodge’s vehicles, vans, SUVs, or any products that make use of the Cummins engines.

For instance, the Dodge Ram is a ‘Dodge Cummins’ because it depends on the Cummins engines for power. Hence, you can outrightly refer to it as Dodge Ram Cummins.

Other codes the P0871 is associated with include:

The P0867, P0868, P0869, P0870, P0872, P0873, P0874, P0875, P0876, P0877, P0878, and P0879 codes.

#1. Functions of the P0871 Code 

The transmission fluid pressure sensor/switch has the specific task of informing the ECU of the current operating pressure inside the transmission.

By storing the p0871 DTC, the voltage signal doesn’t tarry with the usual operating parameters.

Below is a breakdown of the parts that constitute p0871. 

The transmission fluid pressure sensor/switch (TFPS) can be strapped to the side of the valve body right inside the transmission.

In addition, it can also be found screwed into the transmission case. 

The transmission fluid pressure sensor has two basic roles:

  • First, the TFPS converts the transmission fluid pressure to an electrical power signal for the powertrain control module (PCM) or TCM. Other controllers are at this stage informed and using the vehicle’s bus data, the PCM or TCM controls shifts.  
  • The PCM / TCM receives this current signal to detect the operating pressure of the transmission. The signal is also applied when a gear is changed. This code appears if the “C” input doesn’t tarry with the usual operating current stored in the powertrain control module memory. The code can also appear if there’s an internal mechanical problem inside of the transmission. 

Check with your repair manual to know which “C” chain is a match for the vehicle.

#2. P0871 Symptoms: Dodge Cummins

Some of the common symptoms associated with P0871 in Dodge Cummins include:

#1. Limp Mode:

Your Dodge will shift differently, and you may not be able to engage all the gears effectively. 

#2. Engine Light On:

Often, other codes appear with p0871. The codes will be relative to voltage and power.

#3. Unpredictable Shifting:

Soft shifts may occur (Revolutions per minute (RPM) drop slowly while shifting), or there may be a harsh (rapid drop in RPM).

It is best not to keep driving when this code pops up because it can be a warning against transmission failure.

How Do I Fix Code P0871?

The p0871 code is quite a serious issue since it relates to the hydraulic pressure necessary for transmission.

To fix the code, you can take the following steps:

  • First, replace/repair the Transmission high-pressure pump.
  • The substitute temperature sensor of the transmission for another.
  • Replace corroded wiring without any hesitation.
  • Finally, repair the PCM or replace it if necessary.
  • Change the transmission fluid. 
  • Reconstruct transmission

You can also fix the P0871 by providing a separator plate valve. The gasket plate kit has all it takes to control leaks.

P0871 Dodge Cummins Diesel Engine

Cummins engines are remarkable, and they command respect in the automotive engineering world.

In fact, experts consider them diesel engines as they give their trucks more efficiency.

However, even Cummins, as reliable as they come, also encounters some challenges.

Nevertheless, Cummins diesel engine has impressive diagnostic systems which help detect and pinpoint the exact problem its engine encounter at a particular time.

It signifies the driver through an error code. One common error code of the Dodge Cummins is the P0871.

You can consider this a critical issue because it relates to the transmission where an anomaly could cause difficulty in shifting gears and heavily impede drivability.

However, several faults relating to the transmission, especially its fluid pressure, can trigger the P0871 code.

Therefore, I’ll advise that you get a mechanic to quickly take a peek and identify the exact trigger of the P0871 and fix it immediately.

Driving with an active P0871 code in Cummins diesel engines is not a prudent course, not even for a quarter-mile.

Tranny Code P0871

The transmission diagnostic trouble code P0871 will display on your vehicle’s dashboard, provided your “code reader” is available on your car’s onboard computer.

You can take notice of these signs when your dashboard displays a check engine or check engine light on.

Most local auto parts stores do not charge for scanning your vehicle to determine the codes in the onboard computer.

However, AutoZone and other shops scan for free for auto users. An alternative is to buy a basic code reader from Amazon, and if at all, at your local shops. 

Additionally, you can move your car to any local but trustworthy repair shop to diagnose and estimate the maintenance cost. 

Why P0871 Issue Again?

The P0871 code may never cease to occur in your RFE transmission Dodge if the listed causes are in view.

The occurrence or reoccurrence of the p0871 might be due to the following:

  • Inadequate transmission fluid
  • Damaged transmission high-pressure pump
  • Spoiled transmission temperature sensor
  • Ineffective transmission
  • Faulty PCM
  • Overheating vehicle engine

Conclusion

Dodge Cummins engines are of special historical interest; their workability or functioning is commendable.

Unfortunately, Dodge Cummins engines can also suffer issues despite the respect they command.

The p0871 is a diagnostic trouble code related to the transmission for almost all vehicle engines, including the Dodge Cummins.

However, the code indicates a problematic situation, not necessarily a current one but also a pending one.

Allan

I've been a car enthusiast since I got into my grandfather's Chrysler 300D!
I'm a mechanical engineer and I love to test drive new and old models, especially on my trips where I rent a different car each time. I try to answer any questions you may have about your car as best I can on Wheelfrog!

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