Manifold Absolute Pressure (MAP) Sensor
- MAP sensor circuit malfunction should set a related code in ECM memory. See Fig 1
. If a code is present, see appropriate TESTS W/CODES
article in the ENGINE PERFORMANCE section below. 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.
- G - TESTS W/CODES - 2.2L (S10 Pickup)
- G - TESTS W/CODES - 4.3L (Except S10 Pickup)
- With ignition on and engine off, check MAP sensor parameter using a scan tester connected to Data Link Connector (DLC). Voltage should be as specified. See MAP SENSOR VOLTAGE RANGE table.
- 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. 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 |