Hi all,

New to Volvos. I picked up this S90 recently and have been fixing various things in order to get it roadworthy. As per these two codes, I pulled the IAC valve to find it spotless inside, but testing the leads found the butterfly valve inside to only work in one direction. I pulled two IACs from the junkyard, cleaned and tested both, and both of them fixed the erratic idling.

Now it idles smooth and runs fine, but the codes come back seconds after clearing them. Is there any other thing to check that could be throwing these two codes? I'd rather check anything else that might be throwing these codes before spending a couple hundred bucks on a new IAC, especially considering these two from the junkyard completely fixed the idling issues.

Thanks!


P.S. - just in case it's relevant, I was also getting a P0102 code. After testing and replacing the MAF with a new one, drivability improved and this code went away. I've also replace the PCV system, new spark plugs, cleaned the throttle body while I had it out. I also plan to run fuel system cleaner through it and change the oil soon.