C-1D, Map Sensor Output Check
The MAP sensor measures manifold pressure (vacuum) and sends that signal to ECM. The ECM uses this information for fuel and spark control.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- Check MAP sensor output voltage to ECM. This voltage, without engine running, represents a barometer reading to ECM.
- Applying 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.
- Check vacuum hose to sensor for leaks or restriction. Be sure no other vacuum devices are connected to MAP sensor signal hose.