P0934
Hydraulic Pressure Sensor Circuit Low
- Severity
- High
- Driving
- Drive only to a garage
The hydraulic pressure signal is stuck low - typically shorted to earth or open circuit, though genuinely low pressure produces it too. Without a usable pressure reading the module will not attempt gear changes it cannot guarantee, so the car may refuse to move.
Possible causes
- CommonWiring shorted to earth or open circuit, though genuinely low pressure produces it too between the sensor and the module
- CommonCorroded or fluid-contaminated connector
- CommonFailed pressure sensor
- CommonGenuinely low pressure from a leak or failed pump
- PossibleLoss of the reference voltage or the sensor earth
What you might notice
- Car will not move or will not change gear
- Pump running constantly or not at all
- Transmission warning message
- Check engine light on
What to check, in order
- Check the hydraulic fluid level and look for leaks before assuming an electrical fault. Genuinely low pressure is a real fault, not a sensor problem.
- Unplug the sensor and check whether the low reading persists at the harness.
- Check the reference voltage and earth.
- Inspect the connector for corrosion and fluid contamination.
- Read all codes for pump or pressure unit faults alongside.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Transmission and control modules
P0900P0901P0902P0903P0904P0905P0906P0907P0908P0909P0910P0911P0912P0913P0914P0915P0916P0917P0918P0919P0920P0921P0922P0923P0924P0925P0926P0927P0928P0929P0930P0931P0932P0933P0934P0935P0936P0937P0938P0939P0940P0941P0942P0943P0944P0945P0946P0947P0948P0949P0950P0951P0952P0953P0954P0955P0956P0957P0958P0959P0960P0961P0962P0963P0964P0965P0966P0967P0968P0969P0970P0971P0972P0973P0974P0975P0976P0977P0978P0979P0980P0981P0982P0983P0984P0985P0986P0987P0988P0989P0990P0991P0992P0993P0994P0995P0996P0997P0998P0999