OBD-II trouble code
P0771: Shift Solenoid "E" Performance or Stuck Off
The wiring passed and the hydraulics did not. Stuck off means a spring-returned valve is being held where it rests — which makes this a contamination story, and one that is usually worst on a cold morning.
Quick facts
- System
- Powertrain
- Category
- Transmission / Shift Control
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $150 – $1,400
- DIY difficulty
- Advanced DIY
What does P0771 mean?
P0771 is the performance half of the shift solenoid E pair. Its value lies in what it has already ruled out: the module has commanded the solenoid, the circuit has behaved electrically, and the hydraulic result still did not arrive. If a coil were open or a wire shorted, an electrical code would be stored instead. So this code has already moved the diagnosis past the wiring and into the valve body, and any plan that starts with a multimeter is starting a step behind.
The phrase stuck off deserves unpacking, because it describes a very particular mechanical state. A shift solenoid is spring-returned: energise it and the spool moves, de-energise it and the spring pushes it back to rest. Stuck off means the spool never left rest, so the pressure it was supposed to route was never routed. What makes that distinct from every other failure in the family is that rest is the transmission's designed fallback — it is where everything sits when the vehicle is switched off or the electrics are lost. A solenoid stuck in that position therefore rarely destroys driveability outright. It leaves the transmission running in whatever subset of ratios remains achievable, which is why the complaint so often arrives as "it feels like it's only got a couple of gears" rather than as a breakdown.
The cause profile follows directly from the mechanics. A spring is trying to move the spool and something is stronger than the spring. That something is almost always varnish — the lacquer-like residue that forms when transmission fluid is worked hot for a long time — or debris circulating from wear elsewhere. It is a contamination story rather than a wear story, and that has a useful consequence: what is on the pan magnet and in the fluid is more informative here than any electrical measurement.
There is one more behavioural signature worth knowing, and it inverts what most people expect from an intermittent fault. Varnish stiction is generally at its worst when the transmission is cold and the fluid is thick, and it eases as everything warms and thins. A complaint that is present for the first few miles of every journey and then disappears is a strong contamination signal, and a strong argument for trying a fluid and filter service before condemning the solenoid. A complaint that only appears once hot points somewhere else entirely.
Common causes
- Varnish deposits holding the solenoid spool at its rest position
- Debris from wear elsewhere in the transmission lodged in the valve bore
- Degraded or overheated fluid that has left lacquer on the valve body surfaces
- Low fluid level starving the circuit so the commanded pressure never builds
- Clogged filter restricting flow once demand rises
- Worn valve body bore letting pressure bleed past the spool instead of routing it
- Solenoid that energises electrically but no longer generates enough force to move the spool
- Return spring fatigued or broken, leaving the spool positioned unpredictably
Symptoms
- The transmission behaving as though it has fewer usable gears than it should
- The complaint worst on the first few miles of a cold journey and easing as the fluid warms
- Flared or slipping shifts where the affected element should apply
- Shifts that simply do not occur, with the transmission holding the previous ratio
- Limp mode after repeated failed shift attempts
- Check engine light with P0771 stored, frequently alongside P0700
- Fluid that looks dark or smells burnt when checked
Diagnostic steps
- 1.Ask when the fault occurs. Worst cold and improving as the transmission warms is the varnish signature and it points at contamination before it points at a part.
- 2.Check fluid level and condition using the manufacturer's procedure and temperature. Dark, thin or burnt-smelling fluid is a finding, not just a maintenance note.
- 3.Confirm the electrical side is genuinely clear — measure coil resistance and check the connector — not to find the fault, but so that a marginal circuit is not quietly mimicking a hydraulic one.
- 4.Command the solenoid on and off with a scan tool while watching line pressure or gear ratio. No hydraulic response to a good electrical command is the definition of this code and confirms where you are.
- 5.Road test from cold with input and output shaft speeds logged, and note which shifts fail and at what fluid temperature they start working again.
- 6.Drop the pan and inspect the fluid and the magnet before ordering anything. Metal, friction material or visible varnish redirects the job from a solenoid to a valve body and contamination cleanup.
- 7.Inspect the solenoid and its bore for varnish and scoring once accessible. A spool that will not move freely by hand in a clean bore has told you the answer.
- 8.If the transmission uses identical solenoids in multiple positions, swap the suspect one to a different bore and re-test to separate a weak solenoid from a fouled bore.
- 9.After any repair, reset adaptive shift values so the controller is not compensating for behaviour that no longer exists.
Repair cost
$150 – $1,400
A fluid and filter service at $150 to $350 is a more credible fix on this code than on most transmission codes, because the failure mode is a valve being held by contamination and fresh fluid genuinely does free some of them. A solenoid replacement is $250 to $700 fitted. A valve body is $600 to $1,400. If the pan inspection turns up friction material rather than varnish, expect the estimate to move toward an overhaul — but that finding comes from the pan, not from the code, so insist on the inspection before accepting the higher number.
Estimate your repair
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Open the Repair Cost Estimator with transmission fluid service 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.