Note. For circuit reference, see appropriate SYSTEM WIRING DIAGRAMS article.
Circuit Description
Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure (vacuum). A 5-volt reference is applied to sensor. A variable resistor moves in relation to manifold pressure and a voltage signal is returned to VCM through MAP signal circuit. Voltage signal varies from 1.0-1.5 volts at closed throttle to 4.0-4.5 volts at wide open throttle (low vacuum). VCM utilizes MAP signal and throttle position to determine fuel delivery. If VCM detects MAP sensor voltage greater than 4.4 volts for more than one second, DTC P0108 will set.
For duplication of DTC, ensure no TP sensor DTCs are set, engine is running, and throttle position is less then 0.4 percent when engine speed is less than 1200 RPM, or throttle position is less than 20 percent when engine speed is greater than 1200 RPM.