The CEL in a friend's 1997 Acura CL (with the J30 V6) came on a while ago, and checking with my scanguage showed DTC P0505 - Idle Air Control malfunction. I cleared the code but a couple of days later it came back on.
A couple weeks ago we took the IAC valve off and cleaned it. It was *really* dirty. We'd disconnected the battery while doing the job and when we were finished I verified no DTCs were showing with everything hooked back up.
Unfortunately, a couple days later the light came back on. I haven't been able to verify the code is the same because something has since happened to the wiring on the car and the radio, lighter, and OBD2 port are powerless (which is really a different issue -- and I'm not trying to fix that one) but it's most likely the same code because it's still accompanied by periodic low/rough idle as it was before we cleaned the IAC valve.
He's going to get the electrical issue sorted out with his mechanic, but I'd like to help him get the IAC problem fixed this weekend if possible. At this point I can think of a few possibilities:
1) The IAC valve is bad and needs to be replaced.
2) The problem is actually vacuum leaks, or the TB gasket didn't go back on as well as we thought it did when reassembling the first time around (I doubt this because it seems like there would be surging/high idle, not low idle, right?).
3) The problem is in the circuit, but not the valve.
4) The problem is something else that I don't understand.
I'd like to be fairly confident before I recommend that he spends $130-$150 on a part. Is it likely that the valve is suffering mechanical or electrical failure? Anything else I should try or have him try?
If the fix has to wait a couple weeks, are there any potential problems? The car won't stall out because the valve can never fully close (by design) so I think all that will really happen even if it fails completely is high idle will suck and it'll idle low.
A couple weeks ago we took the IAC valve off and cleaned it. It was *really* dirty. We'd disconnected the battery while doing the job and when we were finished I verified no DTCs were showing with everything hooked back up.
Unfortunately, a couple days later the light came back on. I haven't been able to verify the code is the same because something has since happened to the wiring on the car and the radio, lighter, and OBD2 port are powerless (which is really a different issue -- and I'm not trying to fix that one) but it's most likely the same code because it's still accompanied by periodic low/rough idle as it was before we cleaned the IAC valve.
He's going to get the electrical issue sorted out with his mechanic, but I'd like to help him get the IAC problem fixed this weekend if possible. At this point I can think of a few possibilities:
1) The IAC valve is bad and needs to be replaced.
2) The problem is actually vacuum leaks, or the TB gasket didn't go back on as well as we thought it did when reassembling the first time around (I doubt this because it seems like there would be surging/high idle, not low idle, right?).
3) The problem is in the circuit, but not the valve.
4) The problem is something else that I don't understand.
I'd like to be fairly confident before I recommend that he spends $130-$150 on a part. Is it likely that the valve is suffering mechanical or electrical failure? Anything else I should try or have him try?
If the fix has to wait a couple weeks, are there any potential problems? The car won't stall out because the valve can never fully close (by design) so I think all that will really happen even if it fails completely is high idle will suck and it'll idle low.
