SFI Chart C-6, Idle Speed Control (ISC) Check

This test verifies ISC motor operation and checks ISC plunger adjustment.

1. This checks for a high minimum air idle which could cause a sail-on condition. High minimum air idle is okay if engine cannot stay running at minimum air idle.
2. Perform Code P030 diagnosis to identify cause of faulty ISC motor.
3. This determines ISC authority. This is determined by comparing minimum TP sensor value to the maximum ISC extend value. ISC authority should be adjusted to 10-11 degrees of throttle angle.
4. TP sensor idle learn procedure must be performed after ISC plunger adjustment.

Fig 1: SFI Chart C-6 Schematic, Idle Speed Control (ISC) Check

Courtesy of GENERAL MOTORS CORP.

Fig 2: SFI Chart C-6 Diagnostic Flow Chart, Idle Speed Control (ISC) Check

Courtesy of GENERAL MOTORS CORP.