P0944 on 2008-2013 Audi R8 (R8 4.2 R tronic, R8 V10 R tronic) — Hydraulic Pressure Unit Loss of Pressure
1 vehicles · 1 makes · $900-$4,000 repair
How to diagnose and fix P0944: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Audi R8 · 2008–2013
The first-generation R8's optional R tronic single-clutch automated-manual gearbox relies on an electro-hydraulic system (shared with the Lamborghini Gallardo e-gear) to build and hold the pressure that operates the clutch and gear actuators. As miles accumulate, the nitrogen pressure accumulator loses its charge and/or internal seals leak, which forces the electric hydraulic pump to cycle far more often to maintain pressure. The overworked pump then overheats, blows its 30A fuse, or fails outright, and a relay can weld. This is a distinct failure of the hydraulic PRESSURE SOURCE, separate from clutch-friction wear or the later S tronic mechatronic actuator. When pressure is lost the car can become stuck in neutral and undriveable, sometimes with little warning. Audi TSB 2027842 (35 11-04, 2008 R8 R-tronic) addresses this failure mode, citing three root causes: an external hydraulic fluid leak, an internal leak with fluid loss, and an internal leak without fluid loss from sealing elements damaged by poor deburring of the valve ports in the hydraulic unit.
Common Symptoms
- Gearbox / transmission malfunction warning message
- Hydraulic pump audibly runs for more than ~10 seconds (e.g. when a door is opened) or cycles constantly
- Car stuck in neutral or will not select a gear
- Intermittent or harsh shifting before total failure
- Blown 30A pump fuse
How to Fix
Diagnose with a scan tool: a failing accumulator/pump typically stores P17BF (hydraulic pump play protection) and/or P0944 (loss of hydraulic pressure). Standard repair order is to renew the relatively inexpensive pressure accumulator first; if pressure loss persists, replace the hydraulic pump (and its relay/fuse), and only then suspect the hydraulic clutch/gear actuator or the solenoid-valve O-rings. Fresh, correct-spec hydraulic fluid and a proper bleed with a diagnostic tool are required. Owners are advised not to drive the car (except directly to a shop) once the pump is heard running continuously or shifting becomes intermittent.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- R tronic hydraulic pressure accumulator (nitrogen bladder accumulator)OEM086325585Cross-refMLR Engineering 88.204.3 (upgraded-design accumulator, sold , Magneti Marelli 086-325-585 / 86325585 (same OEM casting, La$240–$615
Confirmed to fit BOTH engines: 4.2L V8 R tronic (transmission codes KBC, LFR, MBB) and 5.2L V10 R tronic (codes LJM, MAZ
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (1)
Find P0944 by make
Browse every documented model and issue for your make.
P0944 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0944 mean?
P0944 stands for "Hydraulic Pressure Unit Loss of Pressure." The hydraulic pressure unit has lost pressure — the system cannot build or hold the hydraulic pressure needed for clutch/shift actuation.
What are the most common causes of P0944?
The most common causes of P0944 are: Internal/external hydraulic leak, Failed pump or motor, Failed accumulator, Faulty pressure control valve. The specific cause varies by vehicle.
How much does it cost to fix P0944?
Repair costs for P0944 range from $900 to $4,000, depending on the vehicle and root cause.
Which vehicles are affected by P0944?
Au7o has documented P0944 across 1 vehicle models from 1 manufacturers: Audi.
Join 700+ subscribers following Au7o for vehicle insights and updates.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.