Chart C1D - Map Output Check

The MAP measures manifold pressure (vacuum) and sends that signal to ECM. ECM uses this information for fuel and spark control.

1. Checks MAP sensor output voltage to ECM. This voltage, without engine running, represents a barometer reading to ECM.
2. Applying 10 in. Hg (34 kPa) vacuum to MAP sensor should cause voltage to be 1.2 volts less than voltage at step 1). Upon applying vacuum to sensor, 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 MAP hose.

Fig 1: Flow Chart C1D, MAP Output Check

Fig 2: Flow Chart C1D, MAP Output Check