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Idle Control System: Notes

Idle speed is controlled by ECU through AAC valve and Fast Idle Control Device (FICD) valve. ECU controls idle speed component(s) based upon signals received from various input devices. If idle speed component(s) test correctly but idle speed is not being regulated properly, check input signals to ECU. See IDLE SPEED SYSTEM INPUT SIGNALS table.

IDLE SPEED SYSTEM INPUT SIGNALS

Application Model Usage
A/C Clutch Signal (1) G20 & M30
Battery Voltage G20 & M30
Crank Angle Sensor G20 & M30
Engine (Coolant) Temperature G20 & M30
Ignition (START) Switch G20 & M30
Neutral Switch (2) G20
Park/Neutral (Inhibitor) Switch G20 & (3) M30
Power Steering Pressure Switch G20 & M30
Throttle Position Sensor G20 & M30
Throttle (Idle) Switch M30
Vehicle Speed Sensor G20 & M30
(1) Signal received from automatic A/C amplifier.
(2) M/T model only.
(3) Signal received from transmission control unit.