Manifold Absolute Pressure (MAP) Sensor Hose
A vacuum hose that connects the intake manifold to the MAP sensor, transmitting manifold pressure readings.
The Manifold Absolute Pressure (MAP) sensor hose is a small rubber or silicone vacuum line that connects a vacuum port on the intake manifold to the sensing port of a remote-mounted MAP sensor. It acts as the conduit transmitting the intake manifold vacuum or boost pressure to the sensor.
If the hose develops cracks, collapses under vacuum, or becomes disconnected, the MAP sensor will receive incorrect pressure readings or read atmospheric pressure constantly. This confuses the ECU, causing it to inject the incorrect amount of fuel, leading to rough running, hard starting, engine stumbling under acceleration, and high fuel consumption.
Because it is subjected to engine heat and oil vapors, the rubber hose will eventually dry rot, harden, and split, particularly at the connection ends. During diagnostics for MAP sensor codes, mechanics check this hose for leaks, soft spots, or blockage before replacing the sensor itself.