P0505 - Idle Control System

[Chopper]

Hello all,

I have recently removed/replaced my head to fix a cracked valve. After getting the whole car back together and starting it up, I will recieve a code P0505 (Idle Control System). I've cleaned the IAC twice (with carb cleaner) and also checked for vacuum leaks. I replaced many of the vacuum lines with the head. I also recieve P0410 (secondary air injection system), but have recieved that code since I got the car and before I did the head job. I also tested the IAC with a voltmeter according to the Chiltons manual, no problems in that test. With the ignition in position 2 (car not running), I can feel the IAC buzzing, which I believe it is supposed to do.

The car idles very smooth after the head job. In D(rive) it will idle around 850-950rpm (according to scan tool), and in P(ark) it will idle around 980-1080rpm. These do seem a bit high, but not unreasonable.

I've cleared the code and driven about 60 miles, it comes back.

Is the IAC the only item that can cause P0505? Or can vacuum leaks also cause this code? Could a worsening of th P0410 air pump code bring this up? Any other ideas?

Thanks!

[TM850R]

Did you check the hard rubber hose that goes to the IAC for cracks. Its not the easiest to check but take off that TB hose and check for some cracks in the IAC hose.

[Chopper]

Don't see anything there yet, but I can look some more. Also, I notice with the scan tool my absolute throttle position is 13.3% with the key in position 2 and the car off. Is this normal for Volvo? I wonder if my throttle linkage is not aligned correctly after my rebuild? Anybody know?