Symptoms of P0994
- 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 P0994
- 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 F 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.