P0971
Pressure Control Solenoid "C" Control Circuit High
- Severity
- High
- Driving
- Drive only to a garage
The control circuit for pressure control solenoid "C" is reading high - typically shorted to voltage or a lost earth. The module cannot control line pressure and will fall back to a failsafe. A circuit shorted to voltage can also hold the solenoid energised, which produces genuinely wrong pressure rather than merely a lost signal.
Possible causes
- CommonWiring shorted to voltage or a lost earth between the module and the solenoid
- CommonCorroded transmission case connector, or fluid wicking into it
- CommonInternal transmission harness failure
- PossibleChafed harness shorting against a supply
- PossibleFailed solenoid
- RareFailed control module driver
What you might notice
- Very harsh, banging shifts
- Transmission stuck in one gear
- Harsh engagement into drive or reverse
- Several solenoid codes stored together
- Check engine light on
What to check, in order
- Check the solenoid earth before assuming a shorted signal wire - a lost earth commonly drives a circuit high.
- Disconnect at the case connector and check whether the high reading persists at the harness side.
- Pull the case connector and inspect for fluid and corrosion.
- Follow the harness looking for a chafe point where it could short against a supply wire or the body.
- Read all codes - several solenoid codes together point at the internal harness or connector.
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