P0777
Pressure Control Solenoid "B" Stuck On
- Severity
- High
- Driving
- Drive only to a garage
Pressure control solenoid "B" is stuck on - it is applying pressure when it has been told not to. Line pressure will be higher than intended, so shifts become abrupt and the transmission may refuse to shift at all. Debris in the fluid holding the solenoid open is the usual reason.
Possible causes
- CommonDebris jamming the solenoid open
- CommonFailed solenoid stuck in the applied position
- CommonSticking valve in the valve body
- PossibleDegraded fluid, varnished internals
- PossibleWiring fault holding the solenoid energised
What you might notice
- Very harsh, banging shifts
- Transmission refusing to shift
- Harsh engagement when selecting drive or reverse
- Limp mode
- Check engine light on
What to check, in order
- Check the fluid level and condition, and look for debris or clutch material.
- Check whether the solenoid circuit is being held energised electrically before assuming a mechanical jam - a shorted wire produces the same symptom and is cheaper to fix.
- Read all codes. Several stuck solenoids at once means contaminated fluid, and cleaning up only one of them will not last.
- Drop the pan and inspect the filter and magnet if you are going in. What you find there tells you whether the transmission is worth repairing.
- Very harsh shifts put shock loads through driveline components. Do not drive it like this any longer than necessary.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Transmission
P0700P0701P0702P0703P0704P0705P0706P0707P0708P0709P0710P0711P0712P0713P0714P0715P0716P0717P0718P0719P0720P0721P0722P0723P0724P0725P0726P0727P0728P0729P0730P0731P0732P0733P0734P0735P0736P0737P0738P0739P0740P0741P0742P0743P0744P0745P0746P0747P0748P0749P0750P0751P0752P0753P0754P0755P0756P0757P0758P0759P0760P0761P0762P0763P0764P0765P0766P0767P0768P0769P0770P0771P0772P0773P0774P0775P0776P0777P0778P0779P0780P0781P0782P0783P0784P0785P0786P0787P0788P0789P0790P0791P0792P0793P0794P0795P0796P0797P0798P0799