Anyone ever see an ECM/PCM where the IAC driver failed?

I've got a 16181333 PCM. I verified the wiring from the PCM connector to the IAC is fine. Using a known good iac, if I retract or extend the IAC using the laptop to command 1-160 steps sometimes it will retract, sometimes it will do nothing at all. I can't ever get it to extend.

-- Joe

 

Rare, but I have had ECMs with failed IAC drivers. Usually they just don't work.

Can use LEDs to display the signal from the driver. Either one bi-color on each bridge, or two single color on each bridge. A 1K resistor works as they are usually a 12 volt signal.

RBob.

 

Hello,

I was going to order a IAC noid as I should have one anyway.

The car will idle at 1200rpm warm, with a target idle of 625, and iac steps of 0.

Playing with $EE_HACK, I can set the target steps from 0-160, but like I said I saw it move like once and only retract (160). It didn't even go all the way.

I did a continuity test of the wires and physically checked them from the C1 connector to the iac connector, they are fine. Tried two different off-shelf IAC's.

Do you have any experience with $EE on 16181333 ? I'd assume if the software allows you to test the valve with output steps, it actually works. So I'm guessing the problem is the PCM ?

Thanks!
-- Joe

 

> Do you have any experience with $EE on 16181333 ?

I don't. I'm not sure but can the IAC be extended via the ALDL jumper and key-on, engine-off? If so just don't shoot the pintle out.

RBob.