When the TP sensor’s signal indicates closed throttle position and the engine is idling, the PCM adjusts the idle speed control actuator so that the engine runs at the correct idling speed, regardless of coolant temperature, load and etc. When the additional load applied in the engine, the air flow through the idle speed control actuator is increased momentarily to raise the idling speed.
The PCM monitors engine speed deviation from the target idle engine speed when the vehicle is stopped and the throttle valve opening is stable. The PCM sets DTC P0507 if the difference to the target idle engine speed is higher than the predetermined threshold.
Item
Detecting Condition
Possible Cause
DTC Strategy
Monitor deviation between target idle speed and actual engine speed
A stuck or binding throttle plate
Maladjustment of the accelerator cable
Contact resistance in connectors
Faulty ICA valve
Enable Conditions
Coolant temperature >74?(165.2?)
Closed throttle : 10sec.(continuously)
Vehicle speed = 0
20 sec. after engine start.
10V< Battery voltage <16V
No relevant failure
Engine load < 1000 mg/rev
Threshold Value
Engine speed-Target idle speed > +200rpm (Engine speed too high)
Diagnostic Time
16 seconds
Mil On Condition
2 Driving Cycles
Fig.1) The above waveforms are the voltage signals generated when the ISCA operates. This ISCA is a duty type and the time opened determines the duty amount. The left side is the waveform of the ISCA Opening coil during idle.
The right side is the waveform of the ISCA Closing coil during idle.