P2599 High Generic / SAE

P2599: Turbocharger Boost Control Position Sensor A Performance — Stuck High

Powertrain Auxiliary Inputs, Ventilation and Engine Controls Emissions related

What to do

Describe what the car does, because the code does not say which way the vanes are stuck and the two cases differ:

Strong pull low down, then a sudden cut to reduced power — stuck closed and overboosting. Drive gently and keep off heavy throttle until it is sorted.
Flat everywhere, black smoke — stuck open. Not damaging, but it will not fix itself.

The word "high" refers to the sensor's reading, not to how much boost you have, so it is not a reliable guide on its own.

The cheap checks come first here, and they often find it. A vane mechanism stuck at one end with no response to commands frequently means the actuator has lost what drives it, not that anything is jammed:

On a vacuum-operated turbo, ask for the vacuum at the actuator to be measured — a perished hose, a failed vacuum pump or a dead solenoid all produce this and all cost very little.
On an electric actuator, ask whether it has power, earth and a command signal. On many vehicles the actuator can be bought separately from the turbocharger, which is a fraction of the price — worth asking about specifically, because it is easy to be quoted for the whole assembly.

Only after all of that is the turbocharger itself a fair suspect, and a genuinely failed one usually has play in the shaft and often noise or oil use with it. Insist on recalibration of the actuator after any work — skipping it brings the same code back on a good turbocharger.

What this code means

The vane position feedback is pinned at the high end of its range and does not respond to commands — the mirror of P2598, and the same caution about the wording applies.

"High" names the value the sensor is reporting, not the boost the engine is making and not a particular vane position. Manufacturers differ on which end of the travel is called zero, so the code says the mechanism is stuck at one extreme without settling which. The driving symptom is the discriminator: strong low-speed pull followed by a sudden cut to limp mode means stuck closed and overboosting; nothing low down with black smoke means stuck open.

What is genuinely more likely on this end of the range is a mechanism that has failed to its rest position, and that is a useful thing to know. Vane actuators are usually arranged to fail to a defined default when they lose their drive, because a mechanism with no control has to end up somewhere predictable. So a position pinned at one extreme with no response to commands frequently means the actuator has stopped receiving what moves it rather than that the vanes are jammed — a vacuum supply that has failed outright, a control solenoid that has died, a broken linkage, or an electric actuator with no drive.

That shifts the first checks toward supply rather than mechanism, and they are cheap ones:

On a vacuum-operated turbocharger, test the vacuum actually present at the actuator. A perished hose, a failed vacuum pump or a dead control solenoid leaves the actuator with nothing to work against, and every one of those is a fraction of the price of a turbocharger.
On an electric actuator, confirm it has power, ground and a command signal before anything is condemned. On many vehicles the actuator is supplied separately from the turbocharger — a fact that is easy not to discover and worth asking about explicitly.
Then the mechanism, for carbon seizing the vanes, as at P2563.
Then calibration. As at P2598, an actuator that has not relearned its end stops after work reports a position that disagrees with the command permanently, on hardware that is now perfect.

The turbocharger itself remains the last item on the list, not the first. Genuine bearing failure produces shaft play and usually noise or oil consumption alongside; their absence is an argument against replacing it.

Likely causes

Start here

Faulty turbocharger vane actuator · specialist
Leaking or perished vacuum hose · easy
Carbon build-up seizing the turbocharger vanes · specialist
Failed boost control solenoid · moderate

Less common

Damaged actuator linkage · moderate
Actuator not calibrated after repair · specialist
Faulty turbocharger vane position sensor · moderate

Symptoms

Components involved

Information, not instruction

CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.

Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.

Community experience

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The car — make, model, year and engine. The same fault behaves differently on each.
What you measured, not only what you replaced.
What actually fixed it — or that nothing did, which is worth knowing too.