P0934: Hydraulic Pressure Sensor Circuit Low
What to do
If the car still changes gear normally, this is likely a sensor or wiring fault rather than lost pressure. If it will not select a gear at all, the pressure loss is real and it needs recovering rather than driving.
What this code means
The actuation pressure sensor circuit reads below its valid electrical range, typically a short to ground. The same caution applies as under P0842: a circuit reading low and pressure genuinely being absent are indistinguishable to the module, and the consequences are quite different.
Here the distinction is easy to settle from the driver's seat, because genuine loss of actuation pressure has an unmistakable symptom — the gearbox cannot move anything at all. A car that still changes gear normally with this code stored is telling you the pressure is fine and the sensor circuit is the fault.
Likely causes
Start here
- Wiring shorted to ground · moderate
- Faulty hydraulic pressure sensor · moderate
Less common
- Hydraulic system leak · specialist
- Low hydraulic fluid level · easy
- Corroded transmission connector · 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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