GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC K Pickup - 4WD 🢒 Engine 🢒 Engine Controls - 5.0L and 5.7L 🢒 Intermittent Conditions

Checks

Action

DEFINITION: The problem may or may not turn ON the Malfunction Indicator Lamp (MIL) or store a Diagnostic Trouble Code (DTC).

Preliminary Checks

Refer to Symptoms .

Damaged Electrical Connections or Wiring

Carefully reform all the connector terminals in the problem circuit in order to ensure the proper contact tension. If necessary replace all the connector terminals in the problem circuit in order to ensure the proper contact tension. Refer to Connector Repairs .

An intermittent may be caused by a poor connection, rubbed through wire insulation, or a broken wire inside the insulation.

Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

If a repair is necessary, then refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Road Test

If a visual and physical check does not locate the cause of the problem, drive the vehicle with a J 39200 DMM connected to a suspected circuit or use a scan tool.

When the problem occurs, an abnormal voltage or scan reading indicates the problem may be in that circuit.

Intermittent Components

The following components can cause an intermittent:

    • A defective relay, Control Module driven solenoid, or a switch that can cause an electrical system interference. Normally, the problem will occur when the defective component is operating.
    • The improper installation of electrical devices, such as lights, 2-way radios, electric motors, etc.
    • Route the Ignition Control (IC) wires away from the spark plug wires, ignition system components and the generator. The wire for the engine ground from the Control Module to the ignition system should be a good ground.
    • The ignition secondary voltage shorted to a ground.
    • The Malfunction Indicator Lamp (MIL) circuit or the Diagnostic Test Terminal intermittently shorted to a ground.
    • The Control Module grounds.