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Summary
  • DTC P0944 stands for “Hydraulic Pressure Unit Loss of Pressure.”
  • This is a generic code that’s logged when the PCM detects a loss of hydraulic pressure in the transmission.
  • Code P0944 is commonly caused by low transmission fluid, a faulty transmission oil pump, and a clogged transmission filter.
  • Symptoms of code P0944 include a lit check engine light and issues with transmission shifting.

Hydraulically controlled automatic transmissions/transaxles use valves to control shift timing. These valves create other hydraulic circuit pressures inside the transmission using mainline pressure. If the powertrain control module (PCM) or transmission control module (TCM) detects a significant drop in hydraulic pressure, the vehicle’s computer will register a P0944 code on a scan tool.

What Does the P0944 Code Mean?

Diagnostic trouble code (DTC) P0944 stands for “Hydraulic Pressure Unit Loss of Pressure.” This is a generic powertrain code that applies to select vehicles with OBD-II.

The transmission valve body houses various valves, passages, and solenoids, which direct the flow of transmission fluid. These fluid passages can be widened to create pockets that contain steel, nylon, or rubber check balls.

cross section of a transmission assembly
The PCM will set a P0944 code if it detects a loss of hydraulic pressure in the transmission.

A transmission oil pump is used to deliver transmission fluid and pressurize the system. This pump is usually connected to the engine so that it can quickly respond to the engine’s demands To keep the pump from creating an excessive amount of fluid pressure, the transmission uses a pressure regulator valve or a spool valve and spring combination.

The vehicle’s computer will set a P0944 code if the PCM or TCM detects a loss of hydraulic pressure in the transmission.

Note: The definition of code P0944 might be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P0944 Code?

automatic transmission assembly
One common cause of the P0944 code is internal transmission failure.

What are the Common Symptoms of the P0944 Code?

How to Diagnose the P0944 Code

The P0944 code can be accompanied by other DTCs that are related to the transmission. That means you might observe some symptoms that aren’t listed in this article. Make sure to review your vehicle’s repair manual to learn about your vehicle’s parts and its potential problems. The following video can give you an idea of what the diagnostic process might involve:

However, if you don’t have the required auto repair skills to diagnose your vehicle, we recommend taking your vehicle to an expert. They can thoroughly investigate the problem causing the DTC so you don’t have to take risks with your vehicle.

How to Fix the P0944 Code

There’s no cookie-cutter solution to addressing a P0944 code. You’ll have to take your vehicle’s make and model into account when searching for troubleshooting tips online. For example, what might work to resolve a P0944 code for a Dodge might not work for a Ford. That’s why we recommend looking for a Chilton repair manual. This book can help you identify the underlying problems of your vehicle’s code to figure out the correct fix. You can also search for technical service bulletins that contain specific repair information from your vehicle’s manufacturer. If your vehicle’s problems are common, you might find some help in repair forums. However, if you want more comprehensive factory repair information for your specific vehicle, we recommend getting an ALLDATA subscription.

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Contact Center Manager and Technical Reviewer at CarParts.com

William “Bill” Guzenski has produced hundreds of how-to videos for the automotive community. He’s an ASE Certified Master Automobile Technician, and is affiliated with the Specialty Equipment Market Association (SEMA). He loves attending race events and car shows throughout the country, as well as traveling in his 40-foot motorhome, exploring abandoned mines and ghost towns.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

File Under : OBD-II Trouble Codes
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