P0944Hydraulic Pressure Unit Loss of Pressure
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- 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.
- What you may notice
- 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
- Likely causes
- 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)
- RareLeaking check valve or internal leak in the valve body
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €150 – €6,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.