جلبة صمام التصريف متآكلة أو خلوص في الوصلة

Wear in the wastegate's shaft bush or its linkage, so the valve position no longer matches the actuator's. The actuator moves through its full travel and the valve does not follow, because the play is taken up before anything happens.

Boost becomes imprecise rather than absent. The module commands a position, the feedback reports it reached, and actual boost is wrong — so the codes name performance while both the actuator and the valve are individually serviceable. Play also lets the valve flutter at partial openings, which is audible as a rattle at light throttle and wears the bush further. Check for play by hand with the actuator disconnected, moving the valve arm across its axis rather than through its travel — that is where the wear shows.