Hey all I have been having a issue with my 99' ram with the idle air control. I have replaced the idle air control, I have metered out the wiring that goes from the computer to the IAC. The RPMs run about 1200-1300. Any ideas??

 

ECM has been replaced, Throttle Position sensor is replaced, when checking out the IAC valve when not mounted to back of throttle body, the solenoid does not move when running. Any ideas??

 

From what I understand, energizing the IAC when not in the throttle body will cause the pintle to extend all of the way, screwing it up.

 

I have not gotten the IAC to move at all. Old or new IAC.

 

Check continuity on the wires from the PCM, to the IAC, (four of them) If you don't already have it, you can get the 01 service manual from the faq section here, there will be wiring diagrams in there, showing which pcm connectors you need to play with.

 

Thanks HeyYou I have continuity tested the wires, I have even ohm tested the wires making sure there is not anything melted together of the 4 wires.
I have replaced the IAC with one from autozone, napa. Still nothing. Then even a new IAC after the new ECM was installed.

 

Wow. Wires test good, PCM, and IAC have both been replaced?

Stupid question but, is the IAC bore nice and squeaky clean? Connectors at the PCM clean and tight?

That's just bizarre.

 

Ok, did it bit of research here.

First, when you replaced the IAC, did you disconnect the battery for a few minutes? This act resets the PCM, so, the next time the key is turned to "on", it will run the IAC all the way in, to zero out its readings.

Second: There are two circuits on the four wires. You may see voltage on any two of those at any given time. It may even pulse as the PCM tries to move the IAC motor..... Ground one probe on the engine, and with the key on, check and see if you are getting voltage on any of the wires.

 

Thanks again HeyYou for looking into this more. I have never gotten a voltage down any of the pins in the connector. The bore is clean, I have checked the pins making sure there's not something messed up with them from the PCM. I have changed the IAC both ways no change with the battery negative unplugged or not unplugged. As you can tell I have been down a lot of roads with this issue truck. Any help is appreciated.

 

Hhhhmmmm......

If you aren't getting any voltage at the pins at the IAC connector..... either the PCM is bad, or the wires are.

IAC are in pins 10, 11, 19, and 20, of connector 1. (black one)

Break out your arm with three elbows...... and see if you are getting voltage at the PCM, with everything hooked up, and key on. I know those connectors like to corrode, and cause all sorts of havoc.

You could pull the connector, and insert some short pieces of wire into the cavities (from the back side) so you have an easier time of it when testing.....

Or, if you get really desperate, I am not all that far from you. (about a two hour or so drive, on reasonable roads, something which appears to be in short supply around here at the moment....) Come and see me.