DTC P0505 IDLE AIR CONTROL VALVE (IACV) - AUXILIARY AIR CONTROL (AAC) VALVE - Description
EF & EC-7200prose procedureDTC P0505 IDLE AIR CONTROL VALVE (IACV) — AUXILIARY AIR CONTROL (AAC) VALVE
CG10, CGA3
Description
SYSTEM DESCRIPTION
System Description - Sensors, ECM Function, Actuators
Crankshaft position sensor (POS)
Input Signal to ECMEngine speed
ECM functionECM
ActuatorIACV-AAC valve
Engine coolant temperature sensor
Input Signal to ECMEngine coolant temperature
ECM function
Actuator
Ignition switch
Input Signal to ECMStart signal
ECM function
Actuator
Throttle position sensor
Input Signal to ECMThrottle position
ECM function
Actuator
PNP switch
Input Signal to ECMPark/Neutral position
ECM function
Actuator
Air conditioner switch
Input Signal to ECMAir conditioner operation
ECM function
Actuator
Power steering oil pressure switch
Input Signal to ECMPower steering load signal
ECM function
Actuator
Battery
Input Signal to ECMBattery voltage
ECM function
Actuator
Vehicle speed sensor
Input Signal to ECMVehicle speed
ECM function
Actuator
Cooling fan
Input Signal to ECMCooling fan operation
ECM function
Actuator
Electrical load
Input Signal to ECMElectrical load signal
ECM function
Actuator
This system automatically controls engine idle speed to a specified level. Idle speed is controlled through fine adjustment of the amount of air which bypasses the throttle valve via IACV-AAC valve. The IACV-AAC valve opens and closes according to the signal sent from the ECM. The camshaft position sensor detects the actual engine speed and sends a signal to the ECM. The ECM then controls the IACV-AAC valve so that engine speed coincides with the target value memorized in ECM. The target engine speed is the lowest speed at which the engine can operate steadily. The optimum value stored in the ECM is determined by taking into consideration various engine conditions, such as during warm up, deceleration, and engine load (air conditioner, power steering and cooling fan operation).
COMPONENT DESCRIPTION
The IACV-AAC valve is moved by open and close signals from the ECM. When the open signal is sent to the valve, the amount of air that will flow through the valve increases. The more air that flows through the valve, the higher the idle speed. When the close signal is sent to the valve, the amount of air decreases.