Turbocompresseur usé

A turbocharger worn in its bearings or its wheels, no longer producing the boost it is commanded to. It is the part the codes point at and the part least often actually at fault, because everything between the compressor and the engine can produce an underboost condition with a healthy turbocharger fitted.

Establish wear directly rather than inferring it from boost. Shaft play is the measurement: axial and radial movement beyond specification, oil in the compressor housing, or wheel tips that have touched the housing. A turbocharger that spins freely, holds its shaft and shows clean housings is not worn, whatever the boost reading says — and the fault is then a leak, a wastegate, a vane actuator or a restriction.

When it is genuinely worn, ask why, because the answer changes the repair. Turbochargers fail from oil starvation, oil contamination or foreign object damage far more often than from age. Fitting a new one to the same blocked feed pipe, degraded oil or unfiltered intake destroys it too, sometimes within weeks. Check the oil feed and drain, the filter, and the intake tract for debris before the new unit goes on.