Symptoms of P0940
- 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 P0940
- 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 temperature sensor signal voltage, reference, ground path, open circuits, short-to-voltage faults, and connector terminal fit.
- Compare reported hydraulic temperature with other temperature data and actual operating conditions before diagnosing overheating.
- Inspect sensor connector sealing, internal harness routing, fluid intrusion, and wiring disturbed during transmission service.
Related OBD-II codes
These nearby transmission entries can help compare wording and pin down the fault area.