See if this works.

 

From Service manual
The IAC motor has 4 wires with 4 circuits. Two of
the wires are for 12 volts and ground to supply electrical
current to the motor windings to operate the stepper
motor in one direction. The other 2 wires are also
for 12 volts and ground to supply electrical current to
operate the stepper motor in the opposite direction.

I fail to see where the 5 volts comes into play.

I guess my only option is to try replacing the ECM or put a piece of tape over the check engine light. Its hard to justify spending the money to replace ECM just so I dont have to see the check engine light lit up..

 

I just has this Problem on my 2000 360 and there was a wire wore thru on bottom of coil and a couple pins on the ECM plugs as well as the computer was no good.
I recomend taking it to a dealer get them to check things over, as I wasted 1100 dollars between 2 differnt shops and all the parts they thought it might be.

 

Have you picked up some brake cleaner to clean the IAC port of the TB? How is your air intake tube and the PCV connection? How is the harness condition going away from the plug?

 

I hope someone here can help me. Its 1:30Am here in Austin, Tx. I have spent days looking through forums and threads to fix my problem. I have a P0505 code being thrown by my 1999 Dodge Ram 1500 4x4 with a 318 and about 196,000. Only notable engine modifications would be headers, Kn cold air intake, Accel coil, MSD wires. This was up until about 8 months ago. 8 months ago(when it was running fine) I put in a Hughes Engines Air Gap intake manifold and big gulp throttle body. After doing so, the truck ran great (still does) The idle varies from like 900 to 1200, but barely even noticeable. But the damn check engine light will not go off. When I did the upgrades, I got an SCT tuner with tunes for my specific truck and mods, and it really does run great. Also I can clear the check engine light with the tuner, but it comes right back on. I have changed IAC (idle air control) sensor, the TPS(throttle position sensor), the IAT (map sensor), and both O2 sensors. I didnt care about the light for the longest time because it didnt matter, since I could still drive it. Well, my inspection ran out and i cant get a sticker with the light on. I had an old saturn that i could drive whenever I was doing work on my truck until the trans went in it. So now, I really need to figure this out, and I sure don't have the money to take it to a shop at 125.00 per hour. I'm pretty mechanically inclined and can turn wrenches, just NOT tear into the internals of the motor. If anyone has any suggestions, they would be greatly appreciated. And if I posted this in the wrong place, Im sorry, I dont quite understand the posting part.

 

First, clean the throttle body. Take it off the truck, pull the iac motor out of the backside, and clean that bore really well. You can just wipe off the end of the pintle. Reset codes, see what happens.

If the code comes back, check and see that you are getting 12 volts on TWO pins of the IAC connector. (key on, engine off)

If you are, replace IAC.

If you aren't, verify integrity of wiring between IAC, and PCM. If wiring is good, replace PCM.