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DTC code page

P0766: Shift Solenoid D Performance or Stuck Off

Quick answer: The controller commanded shift-solenoid D but did not see the expected response from the transmission.

Drivers also search this fault as shift solenoid D performance, P0766 stuck off, solenoid D performance code.

Severity: high Family: powertrain Related paths: 10
Meaning

What P0766 usually means

P0766 is the performance-side version of the D-solenoid fault family. Instead of only saying the D path has a problem, it suggests the transmission did not follow through the way the module expected. That often feels like a missing upshift, a flare into the next gear, or a gearbox that works cold but falls apart once heat and fluid flow expose a weak hydraulic response. The diagnosis needs to stay balanced between electrical weakness, sticky valve-body behavior, and true hydraulic follow-through problems.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Ask whether the complaint is worse hot, because temperature-sensitive hydraulic problems often expose P0766 more clearly than a cold test.
  • Check for ratio or other solenoid companion codes that suggest the transmission is failing to complete a shift instead of only losing one circuit.
  • Review freeze-frame to see which shift event and vehicle speed produced the fault.
Driving risk

Can you keep driving?

P0766 can turn a mild shift complaint into repeated flare and clutch wear if driving continues. Limit use if the transmission delays, slips, or refuses normal upshifts.

High urgency: If symptoms are active, reduce driving and diagnose quickly before secondary damage builds.
Likely causes

Common causes behind this code

  • Shift solenoid D is slow, weak, or sticking off
  • Valve-body wear or hydraulic leakage prevents the expected gear change
  • Fluid contamination or overheating reduces hydraulic response quality
  • Intermittent electrical weakness on the D circuit affects command under load
  • Internal clutch-apply or pressure problem makes the commanded shift look incomplete

Cause phrases often tied to this code: sticking shift solenoid D, valve body problem on D path, dirty fluid causing P0766, solenoid D stuck off, hydraulic delay in transmission.

Diagnostic order

Suggested workflow

  1. Review freeze-frame, transmission temperature, and the exact shift event linked to P0766.
  2. Road-test with live data and compare commanded shift behavior to actual feel and ratio evidence.
  3. Inspect the D-solenoid circuit and connector for weakness, corrosion, or intermittent voltage loss.
  4. If the command path stays believable, inspect fluid condition and valve-body response for a stuck-off or delayed hydraulic path.
  5. After repair, confirm the same shift event no longer flares, delays, or forces fail-safe mode.
Avoid guesswork

Common mistakes

  • Calling P0766 a purely electrical code when the performance wording often points into hydraulic gray area.
  • Replacing the whole transmission before proving whether the D path is actually slow, sticky, or underfed.
  • Ignoring how much worse the complaint becomes once the fluid is hot.
Repair path

Practical fix guidance

  • Treat P0766 as a commanded-response problem: prove the command, then prove the hydraulic follow-through.
  • Correct fluid, connector, and valve-body issues before jumping to hard-part conclusions.
  • Do final verification on a fully warm road test, because many P0766 failures only show themselves after temperature rises.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P0766

Useful when the driver knows the wording but not the exact DTC yet.

  • shift solenoid D performance
  • P0766 stuck off
  • solenoid D performance code
Related search intent

Queries this page can answer naturally

  • P0766 code meaning
  • what does P0766 mean
  • shift solenoid D performance
  • P0766 transmission code
FAQ

Quick questions about P0766

How is P0766 different from P0765?

P0765 is the broader D-solenoid malfunction code, while P0766 says the commanded response looks wrong, often like the D path is sticking off or reacting too slowly.

Can a worn valve body cause P0766?

Yes. Valve-body wear and hydraulic leakage are common reasons the expected D-side response never arrives cleanly.

Does P0766 always mean internal transmission damage?

No. Solenoid weakness, dirty fluid, valve-body wear, and wiring trouble can all create the same performance-style failure.