P0766 on Ford: How to Diagnose & Fix
Shift Solenoid D Performance/Stuck Off
2 Ford models · 2 documented issues · 1 critical
P0766 on Ford by model: symptoms, diagnosis and fix
The Ford Fiesta equipped with the DPS6 PowerShift dual-clutch automatic transmission is one of the most complained-about vehicles in recent history. The dry dual-clutch design causes severe shuddering, jerking, hesitation, and complete loss of power during acceleration. The clutch plates overheat and wear prematurely, often before 50,000 miles. The Transmission Control Module (TCM) software frequently fails to adapt properly, causing delayed shifts, harsh engagement, and rollback on hills. Ford faced a class-action lawsuit involving nearly 1.5 million vehicles and a federal settlement was reached.
Common Symptoms
- Violent shuddering or bucking during acceleration from a stop
- Transmission slipping and RPMs flaring without acceleration
- Harsh or jerky shifts between 1st and 2nd gear
- Hesitation or delayed engagement when pressing the gas pedal
- Vehicle rolls backward on hills even with foot on gas
- Grinding or chattering noise from transmission area
- Wrench warning light or transmission malfunction message
How to Fix
Check if your vehicle is covered under Ford's extended warranty or class-action settlement — many Fiestas qualify for free clutch and TCM replacement. If out of warranty, have the clutch assembly and TCM reprogrammed or replaced ($1,500-$3,500). Some owners have had success with multiple TCM reflashes to improve shift quality. As a last resort, some owners have converted to a manual transmission. Avoid the PowerShift entirely when purchasing a used Fiesta — manual transmission models are far more reliable.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Transmission Clutch KitCross-refK70564-01
Fitment confirmed against the ShowMeTheParts catalog for this vehicle's year and engine.
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Sources for this issue (2)
The 8F35 8-speed automatic in 2021-2022 Bronco Sport is documented in Ford bulletins to slip during acceleration from a stop when the transmission is hot, and to set DTC P0766 (shift solenoid D performance) with an illuminated MIL. TSB 21-2268 explicitly names the 2021 Bronco Sport for the P0766 condition; owners also report harsh or erratic shifting.
Common Symptoms
- Transmission slips on acceleration from a stop when warmed up
- Check engine light with DTC P0766
- Harsh, erratic, or delayed shifts
- RPM flare without corresponding acceleration
How to Fix
Diagnose per Ford bulletins: SSM 51011 covers hot-slip on 8F35 units built on/before 16-Mar-2022 (remedy is replacing the internal case-half pump seals, part 7N265), and TSB 21-2268 covers the P0766 MIL. Related TSB 21B55 covers transmission fluid level verification. Have a Ford dealer pull codes and apply the applicable bulletin under warranty.
Sources for this issue (1)
P0766 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0766 mean on a Ford?
P0766 stands for "Shift Solenoid D Performance/Stuck Off." This code means the Transmission/Powertrain Control Module detected that Shift Solenoid 'D' is performing poorly or appears stuck in the off position. Shift solenoids direct hydraulic fluid inside the transmission to engage the proper gears or apply the torque converter clutch, and the module monitors whether commanded shifts actually occur. P0766 sets when solenoid D isn't producing the expected result — the gear change tied to it doesn't happen correctly. This can cause harsh or missed shifts, slipping, or being stuck in a gear, sometimes triggering limp mode. On Ford it is documented across 2 models: Fiesta, Bronco Sport.
What are the most common causes of P0766?
The most common causes of P0766 are: Stuck or failed shift solenoid D, Low or contaminated transmission fluid, Clogged solenoid screen or valve body passage, Open, shorted, or corroded solenoid wiring/connector, Valve body wear or sticking spool valve, Internal hydraulic leak affecting the solenoid circuit, Faulty TCM/PCM solenoid driver. The specific cause varies by vehicle.
How much does it cost to fix P0766 on a Ford?
Repair costs vary widely with the root cause and Ford model; each issue on this page carries its own estimate where one is published.
Looking for P0766 on a different make?
View P0766 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.