General Information

Engine Control
P0620 Alternator Control Circuit - General Information

Component Location





General Description

ISG System has alternator in which there is a communication regulator in order to compensate current loss resulting from repetitive starting. The alternator is duty controlled as current control by PCM with the battery voltage, current, temperature information from battery sensor. The more electrical load, the higher duty output.

DTC Description

PCM set DTC P0620 If it is open or short in Control circuit of alternator. If this DTC is set, Idle stop is not performing.

DTC Detecting Condition





Diagnostic Circuit Diagram





Signal Waveform & Data








Fig.1) Idle Status
Fig.2) Electrical Load (Head Lamp and Defrost are ON

Duty(+) from FR terminal is increased if electrical loads are ON (Head Lamp and Defrost are ON)
ECM controls generation of alternator with duty from FR terminal when electrical Loads turn on