Chart C1D - Map Output Check
- Checks MAP sensor output voltage to ECM. Without engine running, this voltage represents a barometer reading to ECM.
- Applying 10 in. Hg to MAP sensor should cause voltage to be 1.2-2.3 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.
- Check vacuum hose to sensor for leaking or restriction. Be sure no other vacuum devices are connected to MAP hose.