Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Idle air control System/ Circuit / Circuit description
Toyota Corolla (E120): Circuit description
The rotary solenoid type idle air control (iac) valve is located under the throttle body and intake air bypassing the throttle valve flows into the iac valve through the passage.
In this way the intake air volume bypassing the throttle valve is regulated, controls the engine speed.
The ecm operates the iac valve only to perform idle–up and provide feedback for the target idling speed.
Monitor description
The idle speeds are determined depending on the volume of air that passes through the iac valve. When the volume is large, the idle speed becomes higher. When the volume is small, the idle speed becomes lower.
The iac valve controls the air volume that bypasses the throttle valve. The engine control module (ecm) sends duty signals to the iac valve and drives the iac valve stepper motor to determine the air volume that bypasses the throttle valve.
Although the ecm regulates the idle engine rpm with the feedback control in several vehicle stopped, actual idle rpm does not reach the targeted rpm and a learned valve angle of the idle air control (iac) remains at the maximum or remains at the minimum, the ecm determines to detect malfunction in the iac system.
Example: if the rpm difference between the targeted and actual idle engine rpms exceeds 200 rpm (*1) with the vehicle stopped in an idle, and this occurs 5 times, or if the learned value angle of the iac remains at its maximum or minimum angle for 5 seconds, p505 is detected.
P0511 is detected as an open/short circuit in the iac if the rate of duty signal input to the iac valve has stuck at 0 or 100 %.
*1: Threshold rpm is varied by an engine load.
Monitor strategy
Typical enabling condition
Typical malfunction thresholds
Component operating range
Wiring diagram
Other materials:
Switching the display
Press to display or hide the album
title.
If there is additional text, is
displayed.
Press and hold to display the remaining
text.
■USB memory functions
●Depending on the USB memory that is connected to the system, the device itself
may not be operable and certain function ...
Front seat airbag assy rh
Disposal
Hint:
when scrapping vehicles equipped with an srs or disposing of the
front seat airbag assy always first
deploy the airbag in accordance with the procedure described below. If any
abnormality occurs with
the airbag deployment, contact the service dept. Of toyota motor sales ...
Inspection procedure
1 Inspect stop lamp switch assy
Check that the stop light lights up when brake pedal is depressed and
turns off when the brake pedal
is released.
2 Inspect skid control ecu terminal voltage(stp terminal)
Disconnect skid control ecu connector.
measure voltage between termina ...