OBD-II trouble code
P0766: Shift Solenoid "D" Performance or Stuck Off
Shift solenoid D isn't producing the result the transmission commands — it responds electrically but the shift it controls doesn't happen correctly, or the valve is stuck off. This is the performance/hydraulic side of the D-solenoid family, distinct from the electrical code P0768, and it usually calls for a fluid and valve-body check before condemning the solenoid.
Quick facts
- System
- Powertrain
- Category
- Transmission / Shift Control
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $150 – $1,000
- DIY difficulty
- Advanced DIY
What does P0766 mean?
P0766 sets when the TCM commands shift solenoid D to act and the transmission's response doesn't match what it expects — the shift that solenoid should produce is late, missing, or wrong even though the circuit may test electrically fine. Where the electrical code (P0768) catches a clear open, short, or out-of-spec resistance, P0766 is the performance-and-behavior code. 'Stuck off' means the valve is stuck in its de-energized state and won't route pressure when commanded, so there's effectively no shift response from that element.
Because shift solenoids work in combination, a D-solenoid that won't perform corrupts the gears whose pattern depends on it — often a specific upshift or the higher ratios. The affected shift comes in harsh, slips, flares, or simply doesn't complete, and the transmission may run hotter or fall into limp mode to protect itself. The key diagnostic point is that a performance code is not automatically a dead solenoid. Low or dirty fluid, a valve sticking on varnish, a clogged filter, and valve-body wear can all keep the solenoid from delivering its commanded result. That's why fluid level and condition come first, and why P0766 is sometimes solved with a fluid service or valve-body repair rather than a solenoid swap.
As with the other high-lettered solenoid codes, confirm your transmission actually has a solenoid D and identify which physical valve the manufacturer calls 'D' before ordering parts. Left alone, chronic mistimed or missing pressure lets the clutches slip, and slip makes heat that shortens transmission life — so P0766 is worth diagnosing promptly even though the car usually still drives.
Common causes
- Low transmission fluid level
- Dirty or degraded fluid causing valve stiction
- Shift solenoid D sticking off on varnish or debris
- Worn or contaminated valve body bleeding off pressure
- Failed or weak shift solenoid D not delivering its shift
- Restricted transmission filter starving the circuit
- Internal transmission wear affecting the affected clutch or band
Symptoms
- Check engine light on with P0766 stored
- Harsh, delayed, slipping, or missing shift in part of the range
- Transmission won't complete a particular upshift
- Running hotter than normal under load
- Dropping into limp / failsafe mode in some cases
- Reduced fuel economy when the affected clutch slips
Diagnostic steps
- 1.Confirm your transmission has a shift solenoid D and identify which physical valve it is in service data.
- 2.Check transmission fluid level and condition first — low or burnt fluid is a common cause and the cheapest to rule out.
- 3.Scan for companion codes; a general P0700 confirms the TCM has stored transmission faults.
- 4.Read live data and note which shift is affected, consistent with the solenoid D combination.
- 5.Resistance-check shift solenoid D against specification to confirm the electrical side is healthy (which separates it from P0768).
- 6.If the solenoid tests good and fluid is fresh, suspect valve-body wear, sticking, or contamination bleeding off pressure.
Repair cost
$150 – $1,000
A transmission fluid and filter service ($150-$350) is the first step and sometimes the whole fix. Shift solenoid replacement runs roughly $250-$700 depending on whether the pan or valve body must come down. Valve-body repair or replacement is the higher end, and internal mechanical wear costs the most. Confirming the solenoid is electrically healthy before replacing it avoids swapping a good part.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with transmission shift solenoid replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an advanced DIY job. It typically requires specialty tools, scan-tool access, lifting equipment, or careful sequencing to avoid causing new failures. Plan for extended downtime and have a backup vehicle. Most owners are better served by a shop that has done this repair before.