Cause
Blocked or leaking vacuum hose to the sensor
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.
Typically an easy fix. Often worth checking before paying anyone to look.
Codes this can cause (3)
Codes where this is a likely explanation first, rather than merely a possible one.
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.
Others who found this
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- 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.
Sign in or create an account to add what you found about Blocked or leaking vacuum hose to the sensor.