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Home >> Ford >> 1990 >> Probe GL, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests - EEC-IV >> Idle Control System Tests >> ISC Motor (MPI)
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ISC Motor (MPI)

  1. Turn key off and wait 10 seconds. Disconnect harness from ISC motor. Using ohmmeter, put positive lead on ISC connector VPWR terminal and negative lead on ISC terminal. Resistance should be 7-13 ohms. If not, replace ISC motor.
  2. If resistance is 7-13 ohms, measure resistance between either ISC connector terminal and ISC housing. Resistance should be greater than 10 k/ohms. If not, replace ISC motor. If resistance is greater than 10 k/ohms, go to step 3).
  3. Turn ignition on. Using a voltmeter, measure voltage between ISC connector terminals. If voltage is less than 10.5 volts, repair open circuit and repeat test. If voltage is greater than 10.5 volts, turn ignition off. With ISC connector disengaged, connect Breakout Box (014-00322) and leave processor disconnected.
  4. Measure resistance between breakout box test pin No. 21 and ISC terminal on ISC connector. If resistance is greater than 5 ohms, repair open circuit and repeat test. If resistance is less than 5 ohms, measure resistance between breakout box test pin No. 21 and the following test pins: 40, 46, and 60. If resistance is less than 10 k/ohms, repair short circuit and repeat test.
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