Computers and Control Systems: Adjustments

For Early Year Model vehicles, Idle speed adjustment is electronically controlled by the Electronic Control Unit (ECU) and is not adjustable. For Late Year Model vehicles, Idle speed adjustment is electronically controlled by the Single Board Engine Controller II (SBEC II) and is not adjustable. For the late model year vehicle, if idle speed is out of range, refer to Powertrain Management/Fuel Delivery and Air Induction/Testing and Inspection/Procedures.