Code Definition

P0878 — Transmission Fluid Pressure Sensor/Switch D Circuit High

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0878

P0878 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0878 is stored, the module has detected a signal or supply voltage higher than the expected operating range; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0878 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The fault code P0878 is set when the control module detects a high input signal from the Transmission Fluid Pressure Sensor/Switch 'D'. This condition suggests that the sensor or switch is outputting a signal voltage that is higher than the expected range set by the manufacturer. A high signal can indicate several issues, ranging from sensor or switch malfunctions to problems with the wiring or circuit, potentially affecting the accurate monitoring of transmission fluid pressure.

Quick Facts