P0108 - Manifold Absolute Pressure (MAP) Barometric Pressure Circuit High Input

P0108 is set when the Engine Control Unit (ECU) detects a voltage from the Manifold Absolute Pressure (MAP) sensor that is higher than the expected range, typically exceeding 4.5–4.8 Volts for a predefined period. The MAP sensor measures the pressure within the intake manifold and converts it into a voltage signal. A high voltage signal is interpreted by the ECU as high pressure (low vacuum), which normally occurs under wide-open throttle conditions. If this high signal persists during idle or low load, the ECU triggers the code and often enters 'Limp Home' mode as it cannot accurately calculate fuel delivery or ignition timing.