The ECM monitors the idling speed and idling air flow volume to conduct Idle Speed Control (ISC). The ECM determines that the ISC system is malfunctioning if the following conditions are met:
• The learned idling air flow volume remains at the maximum or minimum volume 5 times or more during a driving cycle.
• After driving at 6.25 mph (10 km/h) or more, the actual engine idling speed varies from the target idling speed by between 100 rpm and 200 rpm, 5 times or more during a driving cycle.
If the actual idling speed varies from the target idling speed by more than 200 rpm* 5 times during a driving cycle, the ECM illuminates the MIL and sets the DTC.
*: Threshold idling speed varies with engine load.
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