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Home >> GMC >> 2002 >> Jimmy 2D Utility, Part Time, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 127 (Engine Controls - System & Component Testing) >> Ignition System >> Ignition Relay Diagnosis (5.7L Bi-Fuel) >> Test Description
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Test Description

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The numbers below refer to step numbers in diagnostic procedure.

  1. 1

    The System Check must be performed before proceeding with this diagnostic test. Failure to perform System Check will result in misdiagnosis.
  2. 3

    This step inspects Alternative Fuels Engine Control Module (AF ECM) fuses for opens and also tests voltage supply to fuses.
  3. 5

    This step inspects if AF ECM is powered-up.
  4. 6

    This step tests battery positive and switched ignition voltage circuits to AF ECM.
  5. 7

    This step tests AF ECM ground circuits.
  6. 8

    This step inspects for proper operation of fuel gauge select switch. If switch operates, then ignition relay is ON.
  7. 11

    This step inspects ignition relays ability to turn OFF.
  8. 14

    This step tests ignition relay coils ground circuit. If test light illuminates, then ignition relay must be faulty.
  9. 15

    This step indicates components or circuits that may have caused a fuse to open. Some components may require they be turned on in order to open fuse. An example would be depressing fuel gauge select switch in order to test select switch circuit for a short.