P0766Shift Solenoid D Performance/Stuck Off
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- A shift solenoid is an electrically switched valve in the valve body; the module checks whether its clutch follows the command by gear ratio, shift time or a pressure switch. P0766 means solenoid D is commanded on but its clutch does not follow. Ford checks gear ratio over 10 events (2012) or 3 (2020–23 and the 2023 diesel); on the 6F transmissions solenoid D feeds two clutches, so Ford recognises a solenoid fault when both fail, while a single clutch fault sets ratio codes. Ford's 10R80 bulletins list it with a leaking clutch cylinder; Dodge's Aisin AS6 uses it for solenoid 4. GM does not use P0766.
- What you may notice
- Upper gears (4th–6th) missing, or no reverse or engine braking in first (Ford)
- Slip or engine flare on shifts
- Limp mode
- Check engine light
- Likely causes
- LikelyClutch or brake of this circuit leaking or worn (piston seal, linings)
- PossibleShift spool or proportional valve sticking (dirt, debris)
- PossibleFluid level or quality
- RarePressure switch faulty (Allison, Aisin)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €200 – €3,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.