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Home >> Saturn >> 1996 >> SC1 Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Computerized Engine Controls >> Pcm Power & Ground Check >> Power Circuits
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Power Circuits

  1. Using a voltmeter, check for battery voltage between PCM constant battery power terminals and ground. If battery voltage is not present, check PCM power supply fuse. If fuse is okay, check for open in power supply or PCM wiring.
  2. Turn ignition switch to the ON position. Using a voltmeter, check for battery voltage between PCM ignition power terminals and ground. If battery voltage is not present, check power supply fuse(s). If fuse is okay, check for an open in wiring between fuse and PCM, or check for a defective ignition switch.
  3. Connect voltmeter between ground and PCM start (crank) signal terminal. Turn ignition switch to the START position. Battery voltage should be present between PCM start terminal and ground ONLY when ignition switch is in the START position.
  4. If voltage is not present, check fuse(s). If fuse is okay, check for an open in wiring between fuse and PCM, or check for a defective ignition switch.
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