P0766
Shift Solenoid "D" Performance or Stuck Off
- Severity
- High
- Driving
- Drive only to a garage
Shift solenoid "D" is electrically fine but is not doing its job - it is not shifting when commanded, or is stuck in its off position. The gears that need it will not engage. The circuit checks out, so the problem is hydraulic or mechanical: a jammed solenoid, a sticking valve, or pressure that never arrives.
Possible causes
- CommonSolenoid jammed by debris in the fluid
- CommonSticking valve in the valve body bore
- CommonLow or degraded fluid
- CommonLow line pressure - blocked filter, worn pump, or a pressure control fault
- PossibleWorn clutch pack that will not hold even when pressure arrives
- PossibleInternal leak past a worn seal
What you might notice
- Transmission will not shift into certain gears
- Stuck in one gear
- Flaring between shifts
- Slipping under load
- Check engine light on
What to check, in order
- Check the fluid level and condition first, and look for clutch material.
- Note exactly which gears are missing and whether the pattern is consistent.
- Check for gear ratio codes alongside. Those indicate the clutch is not holding rather than the solenoid not commanding.
- Check the transmission filter if it has never been changed.
- A line pressure test separates a solenoid problem from low system pressure. It is worth doing before buying parts.
- Check whether an adaptation reset is specified after any repair here.
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