Operation CHARM
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GMC Truck
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1983
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S15/T15 4WD Jimmy V6-173 2.8L VIN B 2-bbl
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Repair and Diagnosis
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Powertrain Management
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Computers and Control Systems
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Relays and Modules - Computers and Control Systems
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Idle/Throttle Speed Control Unit
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Description and Operation
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Idle Speed Control (ISC)
Idle Speed Control (ISC)
The
ISC
assembly controls engine idle speed according to ECM programming.
When the throttle lever rests against the
ISC
plunger, the ISC acts as a dashpot on throttle closing per second.