GM Service Manual Online
For 1990-2009 cars only

Inspections

Action

DEFINITION: The problem may or may not turn ON the malfunction indicator lamp (MIL) or store a diagnostic trouble code (DTC).

Preliminary Inspections

Refer to Symptoms - Engine Controls .

Damaged Electrical Connections or Wiring

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

Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

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 in Wiring Systems.

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

Road Test

If a visual and physical inspection does not locate the cause of the problem, drive the vehicle with a 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 conditions can cause an intermittent:

    • Normally, the problem will occur when the defective component, relay, solenoid, or switch is operating.
    • The improper installation of electrical devices, such as lights, 2-way radios, electric motors, etc.
    • The ignition secondary voltage shorted to a ground
    • The malfunction indicator lamp (MIL) circuit