Wile.E.Coyote
New member
Just wanted to see if I could help everyone else out with what I learned in my experience with this code, I didn't see any other threads on it.
I went to Moab with my 4.0L V6 4wd sport with 105,000 on the odo. Had K&N and emission filter removal. Spent 3 days on the trails, after day 2 I got a MIL indicator, check engine light. Got code pulled and it was P0505 - Idle Air Control.
I wasn't too worried, assumed it was the dusty red dirt and the MIL light would come off and on for the next few days. There didn't seem to be any adverse effect on performance. It idled fine even when the check engine light was on.
When I got home the light had come on permanently and I decided to remove and inspect most of the upper intake, cleaned and re-oiled the K&N per spec and then removed the throttle body. The shop manual specifies that you check the pcv valve first with a P0505 so I pulled it, cleaned it as best I could and reinstalled. When I get to an auto parts store I'll replace it, can't hurt. That didn't seem to be the issue so I went back to throttle body, because that's what the shop manual said to check next. When I pulled it there was significant gunk built up around the butterfly valve on both sides, sorry I don't have picture. It was black gunk almost like gum all over where the valve contacts the housing. Plus a lot of red fine dirt from Moab. I cleaned the shit out of it with brake cleaner and oiled the butterfly valve hinges and then cleaned the rest of the intake system as best I could.
Before putting everything back together I tested the throttle body by removing it but keeping the wire connector on there, then turning the ignition to ON and having someone step in the accelerator and watching the valve. The valve seemed to open fine and motor worked fine, so i put everything back together.
When I started the car up it revved like crazy and idled at 2000rpm. I drove it for a bit and it clearly was letting too much air in, idle was high in both park and drive and it was shifting roughly. I assumed that the ECU needed to adjust to the new increased flow of air that I'd created by cleaning the gunk from around the valve.
I turned out to right, after several drive cycles eventually the ECU adjusted and the idle is good and no more MIL light. I might have been able to accomplish the same adjustment by resetting the ECU by disconnecting the battery. Hope this helps y'all.
I went to Moab with my 4.0L V6 4wd sport with 105,000 on the odo. Had K&N and emission filter removal. Spent 3 days on the trails, after day 2 I got a MIL indicator, check engine light. Got code pulled and it was P0505 - Idle Air Control.
I wasn't too worried, assumed it was the dusty red dirt and the MIL light would come off and on for the next few days. There didn't seem to be any adverse effect on performance. It idled fine even when the check engine light was on.
When I got home the light had come on permanently and I decided to remove and inspect most of the upper intake, cleaned and re-oiled the K&N per spec and then removed the throttle body. The shop manual specifies that you check the pcv valve first with a P0505 so I pulled it, cleaned it as best I could and reinstalled. When I get to an auto parts store I'll replace it, can't hurt. That didn't seem to be the issue so I went back to throttle body, because that's what the shop manual said to check next. When I pulled it there was significant gunk built up around the butterfly valve on both sides, sorry I don't have picture. It was black gunk almost like gum all over where the valve contacts the housing. Plus a lot of red fine dirt from Moab. I cleaned the shit out of it with brake cleaner and oiled the butterfly valve hinges and then cleaned the rest of the intake system as best I could.
Before putting everything back together I tested the throttle body by removing it but keeping the wire connector on there, then turning the ignition to ON and having someone step in the accelerator and watching the valve. The valve seemed to open fine and motor worked fine, so i put everything back together.
When I started the car up it revved like crazy and idled at 2000rpm. I drove it for a bit and it clearly was letting too much air in, idle was high in both park and drive and it was shifting roughly. I assumed that the ECU needed to adjust to the new increased flow of air that I'd created by cleaning the gunk from around the valve.
I turned out to right, after several drive cycles eventually the ECU adjusted and the idle is good and no more MIL light. I might have been able to accomplish the same adjustment by resetting the ECU by disconnecting the battery. Hope this helps y'all.
