P0944 code meaning
Hydraulic Pressure Unit Loss of Pressure
Powertrain system Generic code P09xx codes Check engine light
What P0944 means
The pump runs but the expected hydraulic pressure does not build or collapses. Stellantis names it Loss of Hydraulic Pump Prime: a 2023 STAR case lists it with P0868 and a slow engagement after the vehicle has stood, both set as the only transmission codes with the MIL on, and the fix was a new transmission; an FCA defect file from 2015 also shows it beside line pressure low. Mercedes uses P0944 on the 722.9 automatic with electric auxiliary oil pump for stop-start, as internal fault of that pump; stop-start stops working, and a leaking check valve between converter housing and pump is one cause. Ferrari reads it on its DCT as no system pressure signal with pressure loss. P0943 covers short cycles, P0868 low fluid pressure.
P0944 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 12 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0944
- Check engine or transmission warning light on
- Slow engagement after the vehicle has been parked
- Auto stop-start not available or engine restarts at once
- Slipping, no drive or limp mode
Common causes of P0944
- Most likelyPump loses prime (air drawn in through filter, seal or strainer pipe)
- PossibleBlocked oil strainer or suction tube
- PossibleWorn or failed pump (mechanical or electric)
- Less likelyLeaking check valve or internal leak in the valve body
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hydraulic pressure unitTCM
What each part of P0944 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 9 | Area: transmission. |
| 44 | The exact fault in that area. |
What to do next
- Note P0944 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0944
What does P0944 mean?
P0944 means "Hydraulic Pressure Unit Loss of Pressure". The pump runs but the expected hydraulic pressure does not build or collapses. It is a generic code, so it means the same on every make.
Is it safe to drive with P0944?
Drive gently and only to a workshop. With P0944 the car can go into limp mode (reduced power) to protect itself.
Will P0944 fail an emissions test?
Yes, it can. P0944 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0944 to fix?
Difficulty: workshop only. A typical repair takes 1 to 12 hours of work. This is a job for a workshop.
Will P0944 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.