P0944Generic code

P0944 Code: Hydraulic Pressure Unit Loss of Pressure

The P0944 code means the hydraulic system of an automated manual transmission has lost pressure. The gearbox can be left with no gears or unable to release the clutch. Do not keep driving: check the fluid level and look for leaks first.

Severity
Critical
Can I keep driving?
No, stop and have it checked
Estimated cost
$50 to $1,500
Difficulty
Hard
System
Transmission
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

On this page

What the P0944 code means

Automated manual transmissions (Opel Easytronic, Fiat Dualogic, Toyota MMT, BMW SMG, Ford Durashift, Volkswagen ASG) and many dual-clutch gearboxes use electric or hydraulic actuators to release the clutch, pick the gear plane (selection) and engage the gear (engagement). The transmission computer watches every actuator through position sensors.

With no hydraulic pressure, the clutch actuator cannot release the clutch and the shifts do not happen. The computer sees this through the pressure sensor and stores the P0944 code.

Check the fluid level first and look for leaks. Then move on to the pump, its relay and the accumulator.

P0944 code symptoms

  • The vehicle will not start or will not go into gear.
  • The gearbox stays in one gear or in neutral.
  • Warning light or message on the dash.

Likely causes of the P0944 code

  1. Hydraulic fluid leak in the lines, fittings or actuator.
  2. Low fluid level in the hydraulic reservoir.
  3. Pump or pump relay not building pressure.
  4. Accumulator with no gas charge, so it cannot hold pressure.

How to diagnose the P0944 code step by step

  1. Check the fluid level.
  2. Look for leaks at the actuator and the lines.
  3. Test the pump and its relay.

How to fix the P0944 code

  • Repair the leak and refill with the specified fluid.
  • Replace the pump, the relay or the accumulator.
  • Run the learning procedures.

Only clear the P0944 code once the pressure is holding again.

Technical reference data

  • Use the hydraulic fluid specified by the manufacturer.
  • Reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

These are the makes where this family of codes appears most. In many hydraulic systems the actuator fluid is a specific one, and the reservoir should be checked regularly.

P0944 on Opel

Very common on the Opel Easytronic.

P0944 on Fiat

Very common on the Fiat Dualogic.

P0944 on Toyota

Very common on the Toyota MMT.

P0944 on Smart

Very common on Smart cars fitted with this gearbox type.

P0944 on BMW

Very common on the BMW SMG.

Frequently asked questions about P0944

Can I drive with a P0944 code?
It is not recommended. The gearbox can be left without gears, and you could be stranded in traffic.
What should I check first?
The fluid level in the hydraulic reservoir. A low level usually means a leak somewhere in the system.
Is it serious?
Yes. Without pressure the clutch cannot be released and the car cannot change gears.
How much does it cost to fix P0944?
Between $50 and $1,500. Topping up fluid and fixing a fitting is cheap, while a pump or accumulator costs more.
What does the P0944 code mean?
It means the hydraulic pressure that runs the clutch and shifts has dropped. The computer picked this up from the pressure sensor.
What is the most common cause of P0944?
A fluid leak or a low level in the reservoir. A worn pump or an accumulator with no charge is the next suspect.

Related codes

Questions about the P0944 code

There are no questions about this code yet. Tell us about your case: vehicle, symptoms and what you have already checked.