P0938
Hydraulic Oil Temperature Sensor Range/Performance
- Severity
- Medium
- Driving
- Drivable — book it in
The hydraulic oil temperature sensor is reading within its electrical range but the value is not plausible - it does not rise as the system warms, rises too fast, or sits at an unlikely figure. The sensor is answering; it is just not telling the truth.
Possible causes
- CommonFailed or drifting temperature sensor
- CommonLow fluid level leaving the sensor uncovered
- CommonHigh resistance in the wiring skewing the reading
- PossibleFluid genuinely overheating from a pump running constantly
- PossibleWrong sensor fitted at a previous repair
What you might notice
- Slow or harsh gear changes
- Temperature reading implausible on the display
- Transmission warning message
- Check engine light on
What to check, in order
- Watch the temperature climb from cold on the live data screen. It should rise smoothly and settle.
- Check the fluid level first - a low level uncovers the sensor and produces this code with a perfectly good sensor.
- Consider whether the fluid really is overheating. A pump running constantly because of a leak will genuinely cook the fluid.
- Check for high resistance in the wiring and connector.
- Read all codes for pressure or pump 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