Monitor Description
The ETCS controls the idle speed and is composed of the throttle motor, which operates the throttle valve, and the throttle position sensor, which detects the opening angle of the throttle valve. The ECM controls the throttle motor by adjusting the throttle valve to the proper opening angle to obtain the target idle speed.
The ECM regulates the idle speed by opening and closing the throttle valve using the ETCS. The ECM concludes that the idle speed control function is malfunctioning if*: 1) the actual idle rpm varies more than the specified amount, or 2) a learned value of the idle speed control remains at the maximum or minimum 5 times or more during a drive cycle. If the idle speed control function is malfunctioning, the ECM will turn on the MIL and set a DTC.
Example:
For a stopped vehicle with an idling engine, DTC P0505 will be set if the engine's targeted rpm and actual rpm exceeds 200 rpm* on 5 different occasions.
P0511 is output when the rate of duty signal inputs to the IAC valve is stuck at 0% or 100% and the ECU determines that the cause is an open or short circuit in the IAC.
HINT:
*: RPM threshold varies with engine load.