What Is P0868 Code On 5.9L Dodge Cummins? (How to Fix It)

P0868 is an insufficient transmission fluid pressure code. This might occur for a variety of reasons, and you must identify the particular cause for this code to be activated in your circumstance.

The transmission fluid pressure is critical to the proper operation of your gearbox. The transmission fluid pressure sensor informs the ECU about the amount of fluid pressure available at all times. If it senses a shortage, the ECU will store a P0868 DTC.

The P0868 fault code indicates a problem with the transmission fluid pressure. A brief explanation of the P0868 code and definition of P0868 is given below.

What Does P0868 Code Mean On 5.9L Dodge Cummins?

The Line Pressure Sensor (LPS) measures line pressure and regulation is accomplished by varying the duty cycle of the Pressure Control Solenoid (PCS), which is controlled by the Transmission Control System.

The Transmission Control System determines the required line pressure depending on engine and transmission inputs. It evaluates torque input to the transmission and utilizes it as the primary input for calculating desired line pressure.

This is referred to as Torque Based Line Pressure. Furthermore, during shifts, as well as in Park and Neutral, the line pressure is regulated to a predetermined level of 827 or 931kPa to ensure constant shift quality.

The current line pressure is constantly compared to the desired (goal) line pressure.

Symptoms of Getting the P0868 Code on a 5.9L Dodge Cummins

When the P0868 error code is detected, the check engine soon warning light normally illuminates. The car may also have a strong burning odor as a result of the overheated transmission and may begin to smoke. The gearbox may also fail or slide regularly.

So, the symptoms are:

  • The transmission has overheated.
  • The transmission is emitting smoke.
  • Slipping in and out of gear.
  • Trouble code storage and a flashing warning light
  • Additional transmission-related codes may also be present.
  • Transmission slippage can occur in varying degrees.
  • Some or all gears may not be engaged by the transmission.
  • Until the code is addressed, the transmission may be locked into a fail-safe or limp state.
  • Transmission damage can be severe, even lethal, in some situations.

The Causing Factors of the Error Code P0868

The several causing factors of the P0868 code are given below:

  • Transmission fluid that is dirty or depleted.
  • Transmission fluid dripping.
  • Wiring and/or connection damage.
  • Engine overheating.
  • Transmissions pump failure.
  • Transmission fluid pressure sensor failure.
  • The temperature sensor for transmission fluid failed.
  • Inadequate transmission fluid levels as a result of system leakage.
  • Engine overheating due to a faulty transmission temperature sensor
  • PCM malfunction.

How Serious Is Code P0868 on 5.9L Dodge Cummins?

The P0868 diagnostic problem code is particularly significant since it can create more than just drivability concerns. Internal transmission parts can potentially be severely damaged if there is insufficient fluid pressure to function them.

The P0868 error code might disrupt communication. Even if the automobile is in good working order, it should not be used if the P0868 code is recognized.

Driving a vehicle with a P0868 signal can fully ruin the gearbox, which is not only unsafe but also expensive to fix.

How to Solve P0868 Error Code on 5.9L Dodge Cummins?

This error code, like most others, must be diagnosed with a basic OBD-II code scanner.

The steps to solve this problem are given below:

Step 1- Use the scanner to get the freeze frame data as well as any additional issue codes.

Step 2- If the fluid levels have dropped, there is likely a leak in the system. Find the source of the leak and repair it.

Step 3- If the transmission fluid level is adequate; go to the transmission temperature sensor. Only after this procedure should you look for more serious issues, such as a faulty PCM or a failing gearbox.

Step 4- Examine the transmission fluid for leaks. If necessary, repair the gearbox before filling it with the proper amount and kind of fluid. It should be noted that if the existing transmission fluid shows signs of burnout, it must be changed.

Step 5- Examine the transmission wiring and couplings for any signs of damage, such as burns or corrosion. Examine the Transmission Fluid Temperature Sensor for the existence of the reference voltage, which is generally 5 volts.

Step 6- Make sure the sensor has a solid ground signal. Check the resistance if both indications are within the limitations. All collected readings should be compared to the manufacturer’s standards. If the TFT Sensor does not fulfill the specifications, it should be replaced.

How Much Does It Cost To Solve The Error Code P0868?

A straightforward replacement of the transmission fluid pressure sensor would cost considerably under $100 in most situations if done on a do-it-yourself basis.

It’s worth noting that most service companies will require a minimum of one hour of work to change this sensor, which might add another $80 – $120 to the cost depending on where you live.

Depending on the application, rebuilding or repairing a transmission might cost anywhere from $1000 to several thousand dollars. Keep in mind that labor rates in these circumstances vary substantially, so search around for the finest pay per hour.

However, depending on the design and how much retraining of control modules is required, replacing a transmission might take anywhere from four to 10 hours.

Common Mistakes While Solving the P0868 Code

The most common error in P0868 code diagnosis is failing to follow the fundamental OBD-II problem code diagnosis process in the correct sequence. Failure to follow the routine might result in anything from additional cost and trouble to a misdiagnosis.

The following are examples of common P0868 solutions:

  • A faulty transmission fluid sensor was inspected and replaced.
  • Damaged wiring and/or connections must be inspected and repaired/replaced.
  • Topping up the transmission fluid level, but keep in mind that this must be done in conjunction with the repair of fluid leaks.
  • Transmission fluid replacement is required when the transmission fluid is no longer useable.
  • Transmission replacement or rebuilding may be necessary for exceptional instances.

Additional Comments to Consider Regarding the P0868 Code

Although the transmission fluid pressure sensor is always positioned on the transmission box, most transmissions are also outfitted with some additional sensors, making it difficult to precisely identify the fluid pressure sensor.

As a result, non-professional mechanics are highly advised to consult the handbook to correctly determine the fluid pressure sensor to avoid a misdiagnosis.

PCM failure is extremely unusual, but if the PCM is not replaced, it must also be reprogrammed. Be careful that if fluid leaks exist, it may be impossible to verify the fluid level on transmissions with “lifetime” fills since these transmissions lack dipsticks or other measurement equipment.

In these instances, it is preferable to submit the vehicle to a dealer or other qualified repair facility for expert diagnosis and repair.


Vehicles with code P0868 should ideally not be driven, as there is a chance that the gearbox will fail or enter a weak condition suddenly. This might result in an accident if the car abruptly loses power while traveling in traffic.

I hope our chat today provided you with all of the information you required. When it came to the P0868 code on a 5.9L Dodge Cummins, it was all over.

Maintain an eye on the code and try to repair it as soon as feasible. Consider all of my recommendations and, if necessary, seek expert assistance.

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