I got great response last time Thanks !! So my 03 v40 has the 0171 0507 and 0455 not gonna smog trifecta , Put Idle air control from a shiny donor car at pick n pull no change at all . Spent 50 on actual Volvo guy, he suggests 150 more for computer"upgrade " and wouldn't even look at the Jhose solution i got here ( going to get under her myself )even said "he's not sure v40 has one of those"( losing faith in this guy but only out 50 so far) I digress though. I got to googling read that to check IAC to start car ,note idle 1000 rpm ( read elsewhere idle should be 650) disconnect , start and note idle , still 1000 rpm. reconnect.yeppers still 1000 rpm which suggests to me a new one is in order... I'm down to about 150 bucks for this project and not feelin this whole "upgrade " thing will "fix" anything.. does absolutely anything about it actually resolve any issues? I'm thinking if part needs replacing it won't..Sorry to be sissy lala girl here, my "Other car" is a 58 Chevy Del Ray with a 235 and I can wrench on her all day long all by myself but this baffles me Any input truly welcome I have about 2 weeks before tags expire...and it's coming out of my "birthday money "

 

The 0171 is a lean fuel trim code - the 0507 says the idle is too high and the 0455 says there's an EVAP system leak - which all point to some intake air leak some where. You are correct in thinking to look all the way back to the evap cannister, and it won't hurt to clean the idle air valve and MAF (use CRC MAF cleaner not carb cleaner) but I'd be inclined to look closely and spray around all the intake boots and hoses as some are hard to spot visually (like the ones on the right hand side of the intake manifold. I wouldn't simply drop in a new IAC on a guess unless you got a spare or used cheap part to compare to. I'd tend not to believe anything about the computer upgrade as all these codes point to an intake air leak IMHO.

 

Thanks so much !!! Should the idling rpm be just over 1000 and wouldn't rpm change if it were working an I disconnected it, can it be set lower physically somehow and we did clean it before putting in with the spray MAF sensor cleaner which just got replaced, one that came out the little wires were twisty ,actually that is the second one in 6 months ...

 

I've never played with the idle air valve on the S40 but on my old K-Jet Audi, the valve would have a hum to it to show it was working (lol I think I still have a spare in my parts bin). Did you take the valve off to clean? (checking the gasket)

 

Thanks for response Yes we did clean it and looked clean to me, not sure what "dirty" looks like.maybe I'll try to google and see but it was clean nothing funky ,just metal ,so did the one I took off.