P0777 — Pressure Control Solenoid B Stuck On
Pressure control solenoid B does not release line pressure when commanded — output pressure remains at maximum, leading to harsh shifts and elevated stress on the clutch packs and seals.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Pressure control solenoid b
- Valve body
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Solenoid stuck open by debris
- Contaminated ATF clogging the pressure control valve
- Carbon or debris buildup preventing free movement
Possible symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Diagnostic notes
- The malfunction indicator lamp may illuminate
Related codes
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.