Manifold Air Temperature (Mat) Sensor Test (Impulse)
- Remove MAT sensor from intake manifold. The MAT sensor is located near throttle position sensor and contains a Blue/Black and Black/White wire connector.
- Using ohmmeter, check resistance across sensor terminals. Reading should vary with temperature. Replace sensor if not within specification. See MAT SENSOR RESISTANCE SPECIFICATIONS table.
NOTE:
If a MAT sensor problem develops, ECM will set a Code 23A or 23B. For additional testing procedures, see appropriate test procedure in TESTS W/CODES
article.
MAT SENSOR RESISTANCE SPECIFICATIONS
| Temperature °F (°C) | Ohms |
|---|---|
| -40 (-40) | 100,700 |
| 0 (-18) | 25,000 |
| 19 (-7) | 13,500 |
| 39 (4) | 7500 |
| 68 (20) | 3400 |
| 100 (38) | 1800 |
| 158 (70) | 450 |
| 212 (100) | 185 |
CAUTION:
DO NOT attempt to measure O2 sensor output voltage with a conventional voltmeter. Current drain of voltmeter could damage sensor. Oxygen sensor voltage signal can be measured using a 10-megohm (minimum input impedance) digital voltmeter.