Code Definition

P0777 — Pressure Control Solenoid B Stuck On

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

About P0777

P0777 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.

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 P0777 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 P0777 is set when the transmission control module (TCM) or the engine control module (ECM) in vehicles with integrated control systems detects that the pressure control solenoid 'B' is constantly in the 'on' position, regardless of the control commands. This solenoid regulates the hydraulic pressure in the transmission, which is critical for proper gear shifting and operation. A solenoid stuck in the 'on' position can lead to excessive hydraulic pressure, potentially causing harsh shifting, damage to transmission components, or failure to shift gears properly.

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