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Power Circuits

  1. Using DVOM, check for battery voltage between PCM continuous power terminal(s) and ground. If battery voltage is not present, check for open fuse or fusible link. If fuse or fusible link is okay, check for open in circuit between PCM continuous power terminal and power source.
  2. Turn ignition switch to RUN position. Using DVOM, check for battery voltage between PCM ignition power terminals and ground. If battery voltage is not present, check IGN fuse. If fuse is okay, check for open in circuit between battery and ignition switch, and between ignition switch and PCM ignition power terminal. If circuits are okay, check for defective ignition switch.
  3. Connect DVOM between ground and PCM starter (crank) signal terminal. Place gearshift lever in Park. On all vehicles, turn ignition switch to START position. Battery voltage should be present only when ignition switch is in START position.
  4. If voltage is not present, check underhood fuse block fuse No. 5. If fuse is okay, check for open in circuit between ignition switch and PCM starter (crank) signal terminal, or check for defective ignition switch.
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