P0872 Transmission Fluid Pressure Sensor/Switch C Circuit Low

P0872 indicates a low input from transmission fluid pressure sensor or switch C. The pressure feedback signal is below the expected range.

Code details

Generic OBD-II · P0

System: Transmission
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not continue heavy driving with suspected low pressure; confirm whether the low signal is electrical or hydraulic first.

Symptoms of P0872

Harsh, delayed, or slipping shifts, or being stuck in one gear.
Check-engine light, sometimes with limp-home mode.
Flaring RPM or a shudder under load.

Common causes of P0872

Low or degraded transmission fluid.
A failing speed sensor, shift solenoid, or pressure-control circuit.
Wiring, connector, or internal hydraulic/mechanical faults.

Useful checks before replacing parts

Check pressure sensor C signal, reference voltage, ground, connector condition, and internal harness for short-to-ground faults.
Compare pressure data with commanded gear, actual gear, shift timing, and fluid temperature.
Inspect fluid level and condition where serviceable because low actual pressure and low signal faults need separation.

Related OBD-II codes

These nearby transmission entries can help compare wording and pin down the fault area.