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:
Using the key (vehicles
without a smart key system
and with a wireless
remote control function)
Releasing
To release the key, press the button
Folding
To stow the key, press the button
then fold the key.
Using the mechanical key
(vehicles with a smart key
system)
To take out the mechanical key,
slide the release button and take
the key out.
The mechanical key can only be
inserted in o ...
Overhaul
1. Inspect 1st gear thrust clearance
Using a feeler gauge, measure the 1st gear thrust clearance.
Standard clearance:
0.10 – 0.40 Mm (0.0039 – 0.0157 In.)
2. Inspect 2nd gear thrust clearance
Using a dial indicator, measure the 2nd gear thrust clearance.
Standard clearan ...
Using the storage features
List of storage features
1 Glove box
2 Bottle holders
3 Console box
4 Cup holders
CAUTION
■Items that should not be left in the storage spaces
Do not leave glasses, lighters or spray cans in the storage spaces, as this
may cause the following when cabin temperature becomes high: ...