Throttle Position Sensor: Description and Operation

The MVS is a variable resistor used by the ECM to determine throttle position. The ECM transmits a fixed reference (V-Ref) voltage signal through the MVS to ground and is able to determine throttle position by the resistance to current flow. MVS resistance is greatest at closed throttle, and decreases progressively as the throttle is opened. If a malfunction exists in the MVS circuit, the ECM illuminates the ``Check Engine'' lamp as long as engine speed is less than 1500 RPM. When engine speed exceeds 1500 RPM, the lamp will be turned off if it was illuminated due to an MVS malfunction.