P0299 on BMW: causes, affected engines and fix

Documented faults in BMW engines that can trigger P0299

Grouped by engine or model, from most to least important. These are faults with the turbo and with the EGR valve: not all of them will necessarily set the code, and only a diagnosis confirms the cause on your car.

BMW N47

In Serie 1 E87, Serie 1 F20, Serie 3 E90, Serie 3 F30, Serie 5 E60, Serie 5 F10 and 3 more models

- High severityFrequency: CommonTurboTurbo and wastegate valve failureThe N47's turbo does not usually fail from general wear, but because of failure of the wastegate valve, which regulates boost and can seize or lose adjustment, sending fuel consumption soaring; oil leaks from the turbo itself are also common.Repair (garage): €900–€1,800
- Medium severityFrequency: CommonEmissions controlClogged or seized EGR valveYes, as on most diesels of its generation: the N47's EGR valve seizes or clogs with carbon, especially on cars used in town, causing an unstable idle, jerking and loss of power; it is not usually a serious fault if it is cleaned or replaced in time.Repair (garage): €400–€1,500

BMW M47

In Serie 1 E87, Serie 3 E46, Serie 3 E90, Serie 5 E60 and X3 E83

- High severityFrequency: CommonTurboLoss of power and turbo faultsThe M47's turbo does not usually fail suddenly, but it loses power gradually as carbon builds up in the variable geometry; the 150 hp variant built between September 2001 and November 2003 also accounts for turbo faults documented by specialist workshops.

BMW N57

In Serie 3 F30, Serie 5 F10, X3 F25, X4 F26, X5 E70, X5 F15 and 2 more models

- High severityFrequency: CommonTurboLoss of thrust on twin-turbo versions due to the vacuum circuit or the actuatorOn the twin-turbo versions (335d, 535d, xDrive35d/40d) it is common to lose thrust at low revs because of a degraded vacuum circuit or dirt in the actuator that synchronises the turbos, not because of a mechanical turbo failure. The variable-geometry turbo is also cited, more generically.

BMW B47

In Serie 1 F20, Serie 1 F40, Serie 2 F22, Serie 2 Active Tourer F45, Serie 2 Active Tourer U06, Serie 3 F30 and 10 more models

- High severityFrequency: OccasionalTurboPremature turbo wear from neglected maintenanceThe B47's turbo does not have a design flaw as well documented as the N47's, but it can wear out early if oil changes are not respected, with repairs that usually run at around €1,000 to €2,000.Repair (garage): €1,000–€2,000

BMW N54/N55

In Serie 1 E87, Serie 3 E90, Serie 3 F30, Serie 5 E60, Serie 5 F10, Serie 7 F01 and 7 more models

- Medium severityFrequency: CommonTurboTurbo wastegate noise and failureOn the N54 the wastegate rods work loose and produce a metallic rattle; over time they reduce boost pressure. On the N55 it is the electric actuator that fails.

BMW N20

In Serie 1 F20, Serie 2 F22, Serie 3 F30, Serie 4 F32, Serie 5 F10, X1 E84 and 2 more models

- Medium severityFrequency: OccasionalTurboWastegate noise and plastic charge pipe breakageThe N20's single TwinScroll turbo is not, in itself, a frequent point of failure, but over the years wastegate noise or rattle and a loss of pressure can appear, and the plastic pipe that carries air from the turbo to the intercooler can crack, especially with poor maintenance or on modified engines.

BMW B57

In Serie 3 G20, Serie 5 G30, Serie 7 G11, X3 G01, X4 G02, X5 G05 and 2 more models

Common causes of P0299 on any make

From most to least likely, according to the sources.

1Air leaks in the boost hoses or the intercooler, from a split hose or a loose clamp: this is the most common cause.^[1][2]
2Faulty wastegate or its actuator, or a seized turbo, which do not regulate the pressure properly.^[1][2]
3Worn or faulty turbo.^[1][2]
4Blocked intercooler or intake.^[2]

What to check first

The first diagnostic steps, from the most likely and cheapest to check to the most expensive.

1First check the boost hoses and the intercooler: cracks, oil at the joints and loose clamps. This is the most common cause and the cheapest to repair.^[1][2]
2With a diagnostic tool, compare the boost pressure requested by the control unit with the pressure measured by the sensor while you accelerate.^[2]
3Check that the wastegate actuator (or variable geometry actuator) moves and that its rod travels the full stroke, and check the solenoid valve that controls it.^[1][2]

Full guide to P0299: symptoms, diagnosis and whether you can drive

Frequently asked questions

Which BMW engines have faults that can trigger P0299?

BMW N47 (2 faults), BMW M47 (1 fault), BMW N57 (1 fault), BMW B47 (1 fault), BMW N54/N55 (1 fault) and BMW N20 (1 fault). Each fault has its own page with the affected years and versions, the symptoms and the repair cost.

What does code P0299 mean on a BMW?

Turbocharger or supercharger "A": insufficient boost pressure (underboost). The engine control unit has detected that the turbo is not delivering the expected boost pressure: the actual pressure falls below what the engine management requests. That is why, to diagnose it, the requested pressure is compared with the measured pressure using a diagnostic tool. It is a generic OBD-II code: it means the same on a BMW as on any other make.^[1][2]

Can I keep driving with P0299?

Garage soon. You can normally get to the garage by driving gently, often in degraded mode, but you should not carry on using the car as normal: the fault can end up causing more serious engine damage.^[1][2]

Sources

Every fact on this page links to its source. If you find an error, let us know.

Qué significa el código P0299Autodoc Club · Technical documentation · consulted 2 October 2026 · in Spanish
P0299: Turbocharger/Supercharger A Underboost ConditionCarista · Technical documentation · consulted 2 October 2026