P0933: Hydraulic Pressure Sensor Range/Performance
What to do
If you can hear the gearbox pump running very frequently, or almost continuously, mention it — that is a leak somewhere in the actuation hydraulics, and the constant running is what eventually kills the pump. Fixing the leak is cheaper than replacing the pump it destroys.
What this code means
The actuation hydraulic pressure reading is valid but not what it should be. The most diagnostically useful case is pressure that falls faster than it ought to between pump runs, because that is a direct measurement of a leak.
The accumulator is designed to hold pressure so the pump need not run continuously, and how long it holds is therefore a health measurement of the whole circuit. A system that bleeds down in seconds rather than minutes has a leak — a seal, a valve not seating, or an accumulator that has lost its gas charge — and the pump then runs almost constantly to compensate, which is both audible and the reason these pumps fail early on neglected systems.
Likely causes
Start here
- Hydraulic system leak · specialist
- Failed accumulator charge · specialist
- Faulty hydraulic pressure sensor · moderate
Less common
- Faulty hydraulic power unit · specialist
- Low hydraulic fluid level · easy
Symptoms
Components involved
Information, not instruction
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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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