P2712: Hydraulic Power Unit Leakage
Do not keep driving
Get this looked at promptly rather than waiting for symptoms. The system is leaking pressure and the pump is working harder to compensate — acting now is often a seal, and leaving it usually means the pump as well. If the car becomes slow to engage a gear, or refuses to move, stop driving and have it recovered.
What this code means
The transmission's hydraulic power unit is losing pressure.
A hydraulic power unit is a self-contained pump, accumulator and valve pack — it stores pressure so an actuator can be moved instantly, rather than waiting for a pump to spin up. On a transmission it is what operates the clutches and selector forks of an automated manual or a dual-clutch unit.
A leak announces itself by how often the pump runs. The accumulator bleeds down, the pump restarts to top it up, and the interval between runs gets shorter. That cycling is the early warning, and it is also what kills the pump — a pump sized for occasional duty is being asked to run continuously.
So acting on this early is the difference between a seal and a unit. Left alone it ends with a pump that has worn out, and on many vehicles the pump is not separately available from the assembly.
Do not confuse it with the transmission's own fluid pressure, which applies clutches inside a conventional automatic. This is a separate circuit with its own fluid, and confusing the two sends a diagnosis to the wrong system entirely.
Likely causes
Start here
- Hydraulic system leak · specialist
- Faulty hydraulic power unit · specialist
- Failed accumulator · specialist
- Perished seal or O-ring · specialist
Less common
- Low or degraded transmission fluid · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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