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Home >> Cadillac >> 1991 >> DeVille Touring >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Pcm Flow Charts Codes E12 To E99 >> Pcm Code E30, Idle Speed Control Circuit Problem >> Description

Pcm Code E30, Idle Speed Control Circuit Problem: Description

The PCM controls engine idle by increasing or decreasing throttle opening using ISC motor. The ISC will control idle speed anytime throttle switch is closed.

PCM Code E30 sets because the actual RPM never reaches the desired RPM, signifying a slow or failed ISC motor. ISC motor connector is located behind alternator.