[ASJT3]

Hey Guys,

Got my first truck with a 350 Vortec engine, 244K miles. I've got a SES light with code P1509,

"DTC P1509 Idle Speed High - Idle Air Control (IAC) System Not Responding"

That's the only code that's thrown. The engine idles around 1000 RPM and will sometimes surge while driving between 1200-2000 RPM. I googled this code but not much came up. I've seen that a multitude of things can cause high idle, but since I'm getting a code with the symptoms, is this a pretty clear cut case of needing to replace the IAC valve?


Thanks,

Alex