gmc Workshop Repair Guides

GMC Workshop Service and Repair Manuals

Idle Speed Control Motor <--> [Idle/Throttle Speed Control Unit] > < Diagram Information and Instructions|Page 3275
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Idle Speed Control Actuator System

Chart 2 Test Description: Number(s) below refer to circled number(s) on the diagnostic charts.

4. Checks to see cause of no vacuum source.

5. Checks idle speed control solenoid and connections.

6. Checks for open or grounded CKT 439.

7. Checks for open CKT 543 or faulty control module.

Diagnostic Aids: Check all connections. If OK, refer to DIAGNOSIS BY SYMPTOM/ INTERMITTENTS See: Testing and Inspection/Symptom
Related Diagnostic Procedures/Intermittent Condition .

IAC valve reset procedure:

^

Disconnect battery terminal for 10 seconds, then reconnect terminal.

^

Ignition "ON," engine "OFF" for 5 seconds.

^

Ignition "OFF" for 10 seconds.

Idle Speed Control Motor <--> [Idle/Throttle Speed Control Unit] > < Diagram Information and Instructions|Page 3275