Manifold Pressure/Vacuum Sensor: Testing and Inspection

Fig. 005 Chart C-1D MAP Output Check:

Fig. 006 - Wiring Diagram for the Chart C-1D MAP Output Check. VIN U:

CHART C-1D

MANIFOLD ABSOLUTE PRESSURE (MAP) OUTPUT CHECK

2.5L (VIN U) (VIN R)

2.0L (VIN 1) (VIN K)

Circuit Description:
The manifold absolute pressure (MAP) sensor measures manifold pressure and sends that signal to the ECM. The MAP sensor is mainly used to calculate engine load, which is a fundamental input for spark advance and fuel calculations. The MAP sensor is also used to determine barometric pressure.

Test Description: Numbers below refer to circled numbers on diagnostic chart.
1. Checks MAP sensor output voltage to the ECM. This voltage, without the engine running represents barometric pressure to the ECM.

2. Applying 34 kPa (10" Hg) vacuum to the MAP sensor should cause the voltage to decrease 1.2 volts from the voltage read in step 1. When applying vacuum to the sensor the voltage change should be immediate. If the voltage changes slowly the sensor is bad.

3. Carefully check the vacuum hose for leaks or restrictions. No other devices should be connected to the hose.