Monitor Description
The ETCS controls the idling 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 appropriate opening angle to obtain the target idling speed.
The ECM regulates the idling speed by opening and closing the throttle valve using the ETCS. The ECM determines that the idling speed control function is malfunctioning if*: 1) the actual idling speed varies more than specified, or 2) a learned value of the idling speed control remains at the maximum or minimum 5 times or more during a drive cycle. If the idling speed control function is malfunctioning, the ECM turns on the MIL and sets the DTC.
Example:
With the engine idling, DTC P0505 is set when the difference between the engine target and actual rpms exceed 200 rpm* on 5 different occasions.
HINT:
*: RPM threshold varies with engine load.