Symptoms of P0877
- 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 P0877
- 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
- Measure sensor D signal, reference voltage, ground integrity, and circuit continuity while checking for short-to-ground faults.
- Compare live pressure D data with actual line pressure where available, commanded pressure, gear state, and fluid temperature.
- Inspect case connector terminals, internal harness damage, fluid intrusion, sensor connector fit, and related low-reference faults.
Related OBD-II codes
These nearby transmission entries can help compare wording and pin down the fault area.