Manifold Absolute Pressure (Map) Sensor - (4WD 4A-FE)
NOTE:
Manifold Absolute Pressure (MAP) sensor is also known as Vacuum Sensor on 4WD (4A-FE).
- Ensure ignition switch is off. Unplug vacuum sensor electrical connector. Sensor is on center of firewall.
- Turn ignition on, with engine off. Measure voltage between both terminals of sensor harness. See Fig 1. Voltage should be 4-6 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. To test vacuum sensor, disconnect vacuum sensor hose from intake chamber. Turn ignition on with engine off.
- With ECU connectors in place, carefully connect digital (10 meg. resistance) voltmeter to back side of terminals "E2" and "PIM". See Fig 2. Connect hand-held vacuum pump and gauge to sensor vacuum hose.
- Measure voltage drop at specified vacuum reading. See the MAP (VACUUM) SENSOR SPECIFICATIONS table. Replace sensor if defective.
MAP (VACUUM) SENSOR SPECIFICATIONS
| Vacuum: In. Hg | Voltage Drop |
|---|---|
| 3.94 | .3-.5 |
| 7.87 | .7-.9 |
| 11.81 | 1.1-1.3 |
| 15.75 | 1.5-1.7 |
| 19.69 | 1.9-2.1 |