OBD-II trouble code
P0776: Pressure Control Solenoid "B" Performance or Stuck Off
What solenoid "B" actually controls is not standardised — converter clutch apply on one gearbox, a single clutch pack on another, secondary pulley pressure on a CVT. Identify the transmission before diagnosing, because the symptom you have is the clue to which circuit it serves.
Quick facts
- System
- Powertrain
- Category
- Transmission / Pressure Control
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $180 – $1,600
- DIY difficulty
- Shop recommended
What does P0776 mean?
The generic code definition tells you a second pressure control solenoid is not producing the pressure it was told to. What it deliberately does not tell you is what that pressure does, and that is the whole difficulty with this code. The letter is a slot in the manufacturer's own numbering, not a description of a function, and different transmissions assign it to completely different jobs.
On many conventional automatics, solenoid B is the torque converter clutch apply pressure control. On others it regulates the apply pressure for one specific clutch pack, so that shift can be given its own pressure profile. On a continuously variable transmission it is very often secondary pulley pressure — the clamping force that keeps the steel belt or chain from slipping across the pulley faces. Those three jobs fail in three unrelated ways and have three unrelated risk profiles. Diagnosing this code without first identifying the actual transmission, by its tag, RPO or casting, and pulling up the hydraulic schematic for it, is guesswork dressed up as procedure.
The good news is that the symptom carries the answer, because unlike a mainline pressure fault this one is selective. Whatever misbehaves is served by the circuit solenoid B controls, and everything else in the transmission behaves normally. So work backwards. If the complaint is a shudder at light throttle around lockup speeds — owners usually describe it as driving over rumble strips or a vibration through the floor that comes and goes — the circuit is converter clutch apply. If a single upshift is harsh or flares while the rest are clean, the circuit serves that clutch pack. If the vehicle is a CVT and there is a sensation of the engine revving away from road speed under load, the circuit is clamping pressure and the situation is more urgent than the code's tone suggests.
That CVT case deserves a warning of its own. Secondary pressure is what holds a metal belt or chain against the pulley cones, and there is no clutch material involved to wear gradually and warn you. When clamping pressure falls, the belt slips against hardened steel and scores the pulley faces, and scored pulleys are not repairable — the assembly gets replaced. A conventional automatic with a pressure fault degrades over months. A CVT with a clamping pressure fault can be ruined in a much shorter distance. If this code is stored on a CVT, stop driving it and have it recovered rather than driven in.
What causes it is much the same short list as any hydraulic control fault — fluid condition, varnish, a sticking valve, wear in the bore that lets pressure bleed away, or a solenoid that no longer converts current into pressure correctly. The practical difference from the mainline solenoid is access. Secondary pressure control solenoids are more often mounted inside the valve body than externally, which means the pan comes off before anyone can even confirm the part number. That matters when weighing up the job: the labour is already committed by the time you are looking at the solenoid, so it is usually right to inspect the filter, the magnet and the valve body bores in the same visit rather than close it up and hope.
One diagnostic caution. Because solenoid B often controls converter clutch apply, a converter clutch code may be stored alongside this one. That is not a second fault. Fix the pressure control problem, clear both, and see what actually comes back before anyone prices a torque converter.
Common causes
- Oxidised fluid leaving varnish that makes the solenoid's regulating valve stick in its bore
- Low fluid level reducing available pressure in the circuit this solenoid serves
- Wear in the valve body bore around this circuit, letting the regulated pressure bleed away
- Failed or drifting pressure control solenoid B that no longer converts commanded current into pressure
- Debris from clutch or band material holding the valve partly open
- Damaged or leaking sealing rings in the circuit the solenoid feeds
- Restricted filter reducing supply to the valve body
- Wiring, connector or internal harness fault altering the current the coil receives
- On a CVT, secondary pressure circuit wear or damage affecting pulley clamping force
Symptoms
- A single shift that is harsh, delayed or flaring while the rest of the shifts are normal
- Shudder or vibration at light throttle around lockup speeds, often described as driving over rumble strips
- Torque converter clutch codes stored alongside this one
- On a CVT, engine speed rising away from road speed under load, which is belt slip and is urgent
- Transmission temperature higher than normal in the affected condition only
- Limp mode on some applications once the module gives up on the circuit
- Lockup that engages and releases repeatedly at steady speed
- Fuel economy down at cruise where converter lockup is involved
Diagnostic steps
- 1.Identify the exact transmission from its tag, RPO or casting before anything else, and pull up its hydraulic schematic. Solenoid B controls a different circuit on different units and generic advice is worse than none here.
- 2.Characterise the symptom precisely — which shift, which speed, which condition — because the circuit that misbehaves tells you which job this solenoid is doing on this vehicle.
- 3.If the vehicle is a CVT, treat the code as urgent. Secondary pressure is belt clamping force, and slip scores hardened pulley faces that cannot be resurfaced.
- 4.Check fluid level, colour and smell, and use the correct specification fluid for the unit, since CVT and conventional fluids are not interchangeable.
- 5.Read commanded versus actual pressure for this circuit if the transmission supports it, rather than only reading mainline pressure.
- 6.Look at whether shift quality is affected everywhere or only in one condition. Everywhere points at mainline pressure and a different code; only in one condition fits this one.
- 7.Inspect the solenoid connector and internal harness for corrosion, chafe and pin retention issues.
- 8.Resistance-check the solenoid against specification, keeping in mind it can be electrically correct and hydraulically ineffective.
- 9.If the pan has to come off to reach the solenoid, inspect the filter, magnet and valve body bores in the same visit rather than committing the labour twice.
- 10.Where a converter clutch code is stored alongside, repair this fault first and re-test before treating the converter as a separate problem.
Repair cost
$180 – $1,600
A fluid and filter service using the correct specification fluid is $180 to $450, higher on a CVT where the fluid is expensive and the procedure is specific. Solenoid replacement is $300 to $850, and it sits at the higher end more often than the mainline solenoid does because this one is more commonly inside the valve body, so the pan and often the valve body have to come out to reach it. Valve body repair or replacement is $600 to $1,600. On a CVT the figure that matters is not in this range at all: if clamping pressure has been low long enough to score the pulley faces, the replacement assembly or unit is $3,500 to $8,000, which is why a CVT with this code should be recovered rather than driven.
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
Leave this one to a qualified shop. It typically involves emissions-critical components, refrigerant handling, or other work that requires manufacturer-grade tooling, training, or certification. DIY attempts often produce a more expensive problem than the original code.