Manguito de vacío al sensor obstruido o con fugas

The small hose connecting a pressure sensor to what it is meant to measure, blocked or leaking so the sensor reports something else. The sensor is in perfect condition and its reading is honest about the pressure at its port — which is no longer the pressure of interest.

Blocked gives a reading that stops responding, holding near its last value or at atmospheric, so the trace is flat and plausible while the engine's actual conditions change around it. Leaking pulls the reading toward atmospheric, so a manifold vacuum reads shallower than it is and the module infers a load that is not there.

The hose is the cheapest part in the circuit and fails predictably. It hardens with heat and splits at the ends where it pushes onto a stub, or it kinks where it was routed carelessly during other work. Compare the sensor's reading against a known reference with the engine running, and inspect the hose's whole length rather than its ends — a partial blockage from oil or carbon slows the response rather than stopping it, which shows only when conditions change quickly.