Manifold Absolute Pressure (Map) Sensor
WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 1992 Pontiac Trans Sport, 1992 Oldsmobile Silhouette, 1992 Oldsmobile Bravada, 1992 GMC Yukon, and 1992 GMC Vandura Special. However, it is still accessible from the selected car via links, so may be relevant.
- A malfunction in the MAP sensor circuit should set a related code in ECM memory. See Fig 1. If a code is present, see appropriate G - TESTS W/ CODES article. An out-of-calibration sensor may not set a trouble code. Use following procedure to test sensor calibration. If driveability problems exist, MAP sensor failure is suspected, and no MAP code is present, disconnect MAP sensor connector. If driveability condition improves, check MAP vacuum hose for splits, kinks, proper routing and blockage. If no problems are found, replace MAP sensor.
- With ignition on and engine off, check MAP sensor parameter using a scan tester connected to the ALDL connector. Voltage should be as specified in MAP SENSOR VOLTAGE RANGE . If MAP sensor voltage is as specified, go to next step. If voltage is not as specified, check for 5-volt reference supplied to sensor. Check harness integrity. If no problems are evident, replace MAP sensor.
- Using a hand-held vacuum pump, apply 10 in. Hg to MAP sensor and note voltage change. Voltage should drop to about 1.0-2.5 volts less than specified in table. If voltage is not as specified or voltage reading does not immediately follow vacuum change, MAP sensor is faulty.
MAP SENSOR VOLTAGE RANGE
| Altitude (Ft.) | Range (Volts) |
|---|---|
| Below 1000 | 3.8-5.5 |
| 1000-2000 | 3.6-5.3 |
| 2000-3000 | 3.5-5.1 |
| 3000-4000 | 3.3-5.0 |
| 4000-5000 | 3.2-4.8 |
| 5000-6000 | 3.0-4.6 |
| 6000-7000 | 2.9-4.5 |
| 7000-8000 | 2.8-4.3 |
| 8000-9000 | 2.6-4.2 |
| 9000-10,000 | 2.5-4.0 |