Manifold Pressure/Vacuum Sensor: Testing and Inspection

Testing Atmospheric Pressure Sensor:

NOTE: The vacuum sensor and atmospheric pressure sensor are two identical components that are tested in the same manner. Each provides the ECU with different input information. Refer to DESCRIPTION AND OPERATION.

1. Remove vacuum hose and attach vacuum pump to sensor.
2. Turn ignition switch "ON."
3. Probe harness with voltmeter leads without disconnecting electrical plug from sensor.
4. Check voltage between each terminal and ground while alternately applying and releasing vacuum of approximately 0-508 mmHg (0-20 inHg) to sensor.

Atmospheric Pressure Sensor:

5. Compare results to image chart. Terminals "A," "B" and "C" should remain stable while terminal "D" should vary within the specified range.

Reference Chart:

6. If voltage at terminals "A," "B," or "C" is not correct, check wiring harness.
7. If voltages at terminals "A," "B," and "C" are correct but terminal "D" is wrong, replace vacuum sensor.

Vacuum sensor input voltage can be checked at ECU terminal 1E. At idle, voltage should be approximately 1.4V. With engine not running (atmospheric pressure), voltage should be approximately 4V.