Toyota Celica 2005 Repair Manual page 455

DI−256
DTC P0505
DTC P0511
CIRCUIT DESCRIPTION
Throttle Valve
From
Air
Cleaner
Signal
ECM
Valve
DTC No.
Idle air continues to vary greatly from target speed
P0505
(2 trip detection logic)
P0511 Open or short in IAC circuit
2005 CELICA (RM1131U)
DIAGNOSTICS
Idle Air Control System
Idle Air Control Circuit
Intake Air
Chamber
To Cylinder
IAC Valve
P01559
DTC Detecting Condition
− ENGINE (1ZZ−FE)
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, controlling the engine speed.
The ECM operates the IAC valve only to perform idle−up and
provide feedback for the target idling speed.
S Open or short in idle air control (IAC) valve circuit
S Idle air control (IAC) valve is stuck or closed
S A/C switch circuit
S Air induction system
S PCV valve and hose
S ECM
454
Trouble Area
DIC70−02