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Home >> Ford >> 1991 >> Probe LX, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests - 3.0L >> TFI-IV System >> Primary Circuit Test (Except Closed Bowl Distributor)
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Primary Circuit Test (Except Closed Bowl Distributor)

  1. Disconnect terminal "S" at starter relay to allow testing of ignition primary circuit without cranking motor. Ensure ignition is off. Push down on connector tab and disconnect harness connector from TFI module. Ensure TFI module connector is not corroded or swollen. Repair or replace connector as necessary.
    NOTE: If connector is damaged or has broken tabs due to misuse, replace connector. A loose or damaged connector may cause ignition signal faults during KOER operation.
  2. Use a straight pin or terminal spade from an old TFI module to probe connector. Attach negative DVOM lead to distributor base. Avoid ground contact with straight pin or positive terminal lead during testing. Determine if vehicle system has Computer Controlled Dwell (CCD). See IGNITION SYSTEM IDENTIFICATION  . Turn ignition on and measure voltage at following TFI module harness connector terminals: See Figure .
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