P1509 CHEVROLET - Idle Speed High Idle Air Control System Not Responding
- Faulty Idle Air Control (IAC)
- Idle Air Control Valve harness is open or shorted
- Idle Air Control Valve circuit poor electrical connection
- Engine Light ON (or Service Engine Soon Warning Light)
- Engine rough idle
P1509 Chevrolet Description
With the engine runtime 2 minutes, closed throttle, Engine Coolant Temperature (ECT) input over 122°F, Intake Air Temperature (IAT) over 62°F, VSS under 3 mph, the Powertrain Control Module (PCM) detects that the Actual idle speed was 175 rpm higher than desired idle speed.