Vacuum Sensor
- Ensure ignition switch is off. Locate sensor on center of firewall. Unplug vacuum sensor electrical connector. Turn ignition on, with engine off.NOTE: Vacuum sensor is also known as Manifold Absolute Pressure (MAP) sensor.
- Measure voltage between both terminals of sensor harness. See Fig 1. Voltage should be 4.0-6.0 volts. This is reference voltage from ECU. If voltage is not present or low, check wiring and ECU.
- Turn ignition off. Plug in vacuum sensor electrical connector. Disconnect vacuum sensor hose from intake chamber. Turn ignition on with engine off. With ECU connectors in place, connect DVOM to back side of terminals E2 and PIM. See Fig 2.
- Connect hand-held vacuum pump/gauge to sensor vacuum hose. Measure voltage drop at specified vacuum reading. See VACUUM SENSOR SPECIFICATIONS table. Replace sensor if defective.
VACUUM SENSOR SPECIFICATIONS
| In. Hg | Voltage Drop (Volts) |
|---|---|
| 3.94 | .3-.5 |
| 7.9 | .7-.9 |
| 11.8 | 1.1-1.3 |
| 15.7 | 1.5-1.7 |
| 19.7 | 1.9-2.1 |