P0872
Transmission Fluid Pressure Sensor/Switch "C" Circuit Low
- Severity
- High
- Driving
- Drive only to a garage
The signal from transmission fluid pressure sensor or switch "C" is stuck low - usually a short to earth or an open circuit, though genuinely low pressure will produce it too. The module will not trust its own shifts without this reading and will fall back to a failsafe.
Possible causes
- CommonWiring shorted to earth or open between the sensor and the module
- CommonCorroded transmission case connector, or fluid wicking into it
- CommonFailed pressure sensor or switch
- CommonGenuinely low line pressure from low fluid or a worn pump
- PossibleInternal transmission harness failure
- PossibleLoss of the sensor reference voltage
What you might notice
- Transmission stuck in one gear
- Slipping
- Harsh engagement
- Several transmission codes together
- Check engine light on
What to check, in order
- Check the fluid level and condition before assuming an electrical fault. Genuinely low pressure sets a low-pressure code, and that is a real fault rather than a sensor problem.
- Unplug at the case connector and check whether the low reading persists at the harness side.
- Inspect the connector for fluid ingress and corrosion.
- Check the sensor reference voltage where the sensor is a variable type rather than a switch.
- Read all codes together - multiple pressure codes point at pressure, not at sensors.
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
P0800P0801P0802P0803P0804P0805P0806P0807P0808P0809P0810P0811P0812P0813P0814P0815P0816P0817P0818P0819P0820P0821P0822P0823P0824P0825P0826P0827P0828P0829P0830P0831P0832P0833P0834P0835P0836P0837P0838P0839P0840P0841P0842P0843P0844P0845P0846P0847P0848P0849P0850P0851P0852P0853P0854P0855P0856P0857P0858P0859P0860P0861P0862P0863P0864P0865P0866P0867P0868P0869P0870P0871P0872P0873P0874P0875P0876P0877P0878P0879P0880P0881P0882P0883P0884P0885P0886P0887P0888P0889P0890P0891P0892P0893P0894P0895P0896P0897P0898P0899