Chart C1D - Map Output Check

The MAP sensor measures manifold pressure (vacuum) and sends that signal to the ECM. The MAP sensor signal is mainly used for fuel calculations when the ECM is running in the throttle body back-up mode.

1. When the ignition is on and engine not running, MAP sensor signal is used to determine the barometric vacuum to the sensor.
2. The change in voltage should be instantaneous. A slow voltage change indicates a faulty sensor.
3. Check vacuum hose to sensor for leaking or restriction. Be sure no other vacuum devices are connected to the MAP hose.

Fig 1: Chart C1D, MAP Output Check, Schematic

Fig 2: Chart C1D, MAP Output Check