850 GLT has low idle when cold and high idle when warm

WIVolvo850 · Post by **WIVolvo850** » 26 Feb 2009, 09:09

I recently bought a 1995 Volvo 850 GLT that idled poor when cold but was fine when warm. The check engine light was always on and the dealership said they replaced the IAC valve. Checking the engine codes, they all read pointing to the IAC valve. Checking the car, it does appear that the IAC was replaced but the electronic connector wasn't hooked up. After hooking up the connector, the car idles at 500 rpm when cold (and the gas pedal has to be pushed to the floor to start) and will idle between 2000-2500 rpm when warm. The check engine light is not on anymore, but the idle is reverse from how I would expect. Could this be a leak in the vacuum line or is there something else that I should check while I am under the hood? Thank you for any help that you can provide.

Post by **MadeInJapan** » 26 Feb 2009, 17:12

Unhook the battery (make sure you have your radio code) for 15 minutes or so and let the car "learn" how to behave with the IAC connected. So far it's only learned how to behave with it unhooked.

WIVolvo850 · Post by **WIVolvo850** » 27 Feb 2009, 13:59

I unhooked the battery for half hour and drove the car for 2 hours after to relearn with the IAC valve connected. There is no change with the idle. Thank you for the help and is there anything else that you can think of for me to check?

Post by **MadeInJapan** » 27 Feb 2009, 20:34

for it to behave this way, i would think the IAC is bad (I know it's a replacement) or the hoses leading to it have leaks.

WIVolvo850 · Post by **WIVolvo850** » 28 Feb 2009, 05:27

Thank you for your help, I will try to replace it again.

WIVolvo850 · Post by **WIVolvo850** » 04 Mar 2009, 10:35

I have replaced the IAC and put new hoses on but the car still idles the same. Any other thoughts? Congratulations on your new purchase MIJ.