Intermittent idle issue
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Amateur
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Intermittent idle issue
I have a 1999 Ram Van 3500, Roadtrek camper conversion. Every few months my CEL pops on with code P1294 (idle target not reached). Then, after a few days, the CEL turns off on its own.
The last time this happened, I could hear what sounded like a struggling electric motor coming from under the doghouse with the engine off and the key on. Unfortunately, I wasn't able to pull the doghouse off and check it right then, and when I came back later it was no longer making the noise (of course).
I know that P1294 typically indicates a vacuum leak or a bad IAC valve. I've checked for vacuum leaks and been unable to find any, but I'm never 100% confident about that sort of thing. But the fact I can't find a vacuum leak, coupled with the problem being intermittent and self-correcting, and the noise I heard, makes me inclined to think it's a bad IAC.
I'd like to be sure, though, before I fire the parts cannon and go buy a new IAC. Is there a reliable way to test it when the problem is intermittent?
Any suggestions?
Also, I've heard that only the OEM IAC will work properly on these vans, despite several options at local parts stores and online (Rock Auto). Is there any truth to that? I don't mind going to the dealer if it's really necessary, but I'd rather save the money if the outcome's going to be the same.
The last time this happened, I could hear what sounded like a struggling electric motor coming from under the doghouse with the engine off and the key on. Unfortunately, I wasn't able to pull the doghouse off and check it right then, and when I came back later it was no longer making the noise (of course).
I know that P1294 typically indicates a vacuum leak or a bad IAC valve. I've checked for vacuum leaks and been unable to find any, but I'm never 100% confident about that sort of thing. But the fact I can't find a vacuum leak, coupled with the problem being intermittent and self-correcting, and the noise I heard, makes me inclined to think it's a bad IAC.
I'd like to be sure, though, before I fire the parts cannon and go buy a new IAC. Is there a reliable way to test it when the problem is intermittent?
Any suggestions?
Also, I've heard that only the OEM IAC will work properly on these vans, despite several options at local parts stores and online (Rock Auto). Is there any truth to that? I don't mind going to the dealer if it's really necessary, but I'd rather save the money if the outcome's going to be the same.
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From: Clayton MI
First thing I would do, is pull the IAC, clean it, and clean the IAC well till its squeaky clean. Then tend to accumulate a lot of gunk there. (have the battery disconnected while you are playin' with it.) When you have it all back together, hook the battery back up, turn the ignition to On, (and don't touch ANYTHING) count to ten, then start the engine. PCM should figure out idle pretty quick.
Van & CUV Section Moderator
Joined: Nov 2006
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A failing throttle position sensor (TPS) will also make the engine idle erratically. It happened to me two summers ago, the IAC had already been cleaned and replaced, so I changed the TPS with an OEM one and the idle went back to normal.
Thread Starter
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Amateur
Joined: Jan 2011
Posts: 46
Likes: 4
First thing I would do, is pull the IAC, clean it, and clean the IAC well till its squeaky clean. Then tend to accumulate a lot of gunk there. (have the battery disconnected while you are playin' with it.) When you have it all back together, hook the battery back up, turn the ignition to On, (and don't touch ANYTHING) count to ten, then start the engine. PCM should figure out idle pretty quick.
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Joined: Apr 2010
Posts: 87,397
Likes: 4,213
From: Clayton MI
That's what I used. Don't move pintle on the IAC itself though.