Jeep Wrangler/YJ 1987-1995 Repair Guide

Manifold Air Temperature (MAT) Sensor



See Figures 1 and 2

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Fig. Fig. 1: Test the MAT sensor after detaching its electrical connector

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Fig. Fig. 2: MAT sensor and CTS temperature-to-resistance-values

The MAT sensor is tested in the same manner as the coolant temperature sensor, and should yield the same results. The only difference is the pin number of the test points.

  1. Unplug the wire harness connector from the sensor, then test the resistance of the sensor with a digital volt-ohmmeter. The resistance should be less than 1000 ohms with the engine warm. Refer to the chart to check the temperature-to-resistance values and replace the sensor if the resistance is not within the specified range.
  3. Test the resistance of the wire harness between ECU wire harness connector terminal 32 and the sensor connector terminal; also test the resistance between ECU wire harness connector terminal 14 and the sensor connector terminal. Repair the wire harness as necessary if resistance is greater than 1 ohm.


  1. Unplug the MAT sensor electrical connector.
  3. Remove the MAT sensor from the intake manifold, using a deep socket wrench.
  5. Installation is the reverse of removal. Tighten the MAT sensor to 21 ft. lbs. (28 Nm).