How To Fix P0871 Code On Dodge Cummins? (Fully Explained)

Before we discuss the code P0871, we want to talk about the term 68rfe. 68RFE refers to the 6-speed automatic transmission introduced in 2007 with the 6.7L Cummins ISB Diesel engine.  One common complaint with this transmission is DTC P0871.

In technical language, the code p0871 on dodge cummins means “overdrive fluid pressure switch rationality fault.” When the code is described in simple terms, the code indicates the fault in the overdrive fluid pressure switch, which can either be open or closed. It is closed when it should be open, or it is open when it should be closed.

In the rest of the article, we will provide general guidelines on fixing the code and discuss the symptoms, causes, and severity of the code. Keep reading!

What Does Code P0871 Mean On Dodge Cummins?

To reiterate, the code means “overdrive fluid pressure switch rationality fault.” The code indicates the fault in the overdrive fluid pressure switch, which can either be open or closed. It is closed when it should be open, or it is open when it should be closed.

As stated, fluid pressure switches, usually attached to the clutch, require voltage from the TCM. The voltage doesn’t go outside the pre-set range when the pressure switch is open. 

In contrast, the voltage drops to zero when the switch is closed. TCM sets the code when it detects 0 volts in the override switch circuit when the transmission is in 1st to 3rd gear but not in 4th gear.

When the code appears, you must take the necessary steps to fix the issue. Here is a breakdown of the code P20b9 to make your understanding better.

  • P = denotes the vehicle’s powertrain. 
  • 0 = indicates a generic number derived from the SAE standard.
  • 8 = refers to the overdrive fluid pressure switch
  • 71 = indicates an overdrive fluid pressure switch rationality fault

How Serious Is Code P0871 On Dodge Cummins?

There is no way to disregard the code. The P0871 code should be considered severe, and the necessary steps should be taken as soon as it appears. 

Simply put, the code warns you that the transmission is about to overheat. To a certain extent, the code can also be taken as a notification of the transmission failure. So we can say the code is pretty serious.

There are additional consequences too. However, to avoid such major consequences, get the Dodge Cummins to a professional hand. Also, taking quick action may solve the problem fairly cheaply.

What Causes P0871 Code On Dodge Cummins?

A defective temperature sensor or low transmission fluid can be the major reason for the code. There could be some other additional causes. We believe addressing and resolving these causes will almost certainly result in the code being removed.

  • If there is an electrical fault 
  • Hydraulic fault
  • Low fluid level
  • Damaged transmission sensor
  • If there is already an issue with the transmission
  • Engine Overheat
  • Loose connection

Other Symptoms Of Getting P0871 Code On Dodge Cummins

The most obvious symptom is that you will have an overheated transmission. Also, there might be smoke in the transmission area. The other symptoms include the following:

  • Illumination of the check engine light
  • The smell of burning fuel
  • Code is the obvious symptom
  • Fluid leak 
  • Difficulty in shifting the transmission 
  • Transmission slippage

How To Fix Code P0871 On Dodge Cummins?

As if the code has already appeared, you have to fix it. You can fix the code by following the DIY (do it yourself) approach.  Or take professional help? It is a wise decision to fix the issue by getting professional help. 

Note:

Before starting the diagnosis, if you do it on your own, you will need a Dodge Cummins repair service bulletin corresponding to the make, year, and engine size. 

Warning

All the below steps are for informational purposes only. As stated earlier, fixing steps changes corresponding to the make, year, and engine size. Always consult with the repair service bulletin of Dodge Cummins.

Step 1: Diagnostic and road Testing

Before moving on to the next step, you need all the freeze frame data. Connect the OBD scanner and get all the codes. One important note: if the code appears when the gear is below 4, it is more likely the code will appear due to a fault in the valve body. 

After collecting and removing all the data, test drive the vehicle, and rescan. If the code reappears, find the specific cause. Most probably, fluid pressure is the culprit behind the code.

Step 2: Inspect the wiring Connections.

At this stage, visually inspect all the important connections. A damaged wire may contribute to the code being generated. If everything is fine, move on to the next step.

Step 3: Monitor the Pressure 

The mechanic observes the pressure in the overdrive circuit. Observation must occur during the road test, and the transmission should be in either gear 1, 2, or 3. Also, the PSI should be 0. Now, if you see the pressure on the overdrive clutch, most likely, the code is set due to a hydraulic issue.

Step 4: Resistant Test

At this stage, the mechanic may conduct resistance testing on the circuit or different wires. This test is required to check voltage. The voltage should not be less or more than the predetermined or expected range.

Some repairs may fix the issue.

After performing all the above tasks, you may be able to solve the issue. If luck is not with you, you may need to replace parts and components given below:

  • Replace the high-pressure pump
  • You may need to replace the temperature sensor
  • Replace wire if it is corroded
  • New Transmission ( least likely)
  • Replace old transmission oil

How Much Does It Cost To Fix Code P0871 On a Dodge Cummins?

If you try to fix the issue on your own, you need a skill set and tools such as a scanner or ohmmeter. The cost of purchasing them will be somewhere between  $200 and $300.

On the other hand, the cost of hiring a professional for an hour is between $100 and $150. Also, there can be some hidden costs, including taxes or tips.

Now comes the cost of replacement parts. Replacing the transmission costs more than replacing a pressure pump or temperature sensor.

Can You Drive a Dodge Cummins With Code P0871?

As stated, the code P0871 should be taken seriously and solved as soon as possible. You should not drive the car after the code appears. Delay in resolving the issue may come with bad consequences.

Conclusion

When the code appears, a few things need more attention. It is unnecessary to rebuild the transmission if the issue can be resolved by only replacing the fluid. 

On the other hand, overheating transmission is common, so you may think the transmission needs to be removed and repaired. However, it is not necessary.

We believe the writing was helpful, and you have solved the issue in no time. Finally, we advise seeking professional assistance rather than attempting to resolve the problem yourself.

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