Part 2 of 2

Chart C-1D:

Chart C-1D Wiring Diagram:

CIRCUIT DESCRIPTION:

The manifold absolute pressure sensor (MAP) measures manifold pressure (vacuum) and sends that signal to the ECM. The MAP sensor is mainly used for fuel calculation and spark advance. The MAP sensor is also used to determine the barometric pressure.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.



1. Applying 34 kPa (10 inches Hg) vacuum to the MAP sensor should cause the voltage to be 1.5 volts to 2.1 volts less than the voltage at Step 1 G Of Chart C-1D Part 1 Of 2. "MAP voltage output check."

Upon applying vacuum to the sensor, the change in voltage should be instantaneous. A slow voltage change indicates a faulty sensor.

2. Check vacuum hose to sensor for leaking or restriction, Be sure no other vacuum devices are connected to the MAP hose.

NOTE: Make sure the electrical connections stay securely fastened.

3. Disconnect the sensor from the bracket and twist the sensor by hand (only) to check for intermittent connections. Output changes greater than .1 volt indicate a bad sensor.