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hi... have a 1997 Dodge RAM 2500 5.9L automatic 4x4. One day after it had sat for about 3 days since last use I went out and found dead battery. Charged battery and got it started ok but it would die at idle. Holding gas down kept it running fine. Foot off gas and it would slow to a stall. Temorarily I jammed something where adjustment screw on TB is (since plug was still in it) and it ran perfectly. But I've been trying to determine the problem and fix it.

Took Idle Speed Control (ISC) Motor apart: it is the type with three solenoids and VACUUM powered. Car computer sends power and three ground-going signals, one to control each solenoid. Checked continuity of all solenoid colis (44 ohms), powered each with 12V and they work perfectly. Applied vacuum to the input connector and it sucks in and holds position fine. Ok, so what's on the connector coming from the computer?

One pin seems to be low, two seem like open collector, the one that should feed power (in common) to all three solenoids is LOW or OPEN ! Of course, when connected to ISC motor, nothing happens... no movement at all... no buzzing... nothing... cuz there's NO POWER getting to it.

Question: why no power? Could some other sensor or switch or relay or fuse be blocking power from reaching ISC Motor connector? Or some signal telling computer not to supply power to the motor? No obvious broken wires or corrosion, all wires are in wrapped bundles.

Recall battery went dead at same time this first happened... related? Coincidence?? Loss of voltage reset something? Battery seems fine now and truck starts instantly.

HELP!!! :)

Optional Information:
1997 Dodge RAM2500 5.9L

Already Tried:
Tested ISC Motor -- seems ok. Tested TP Sensor -- seems ok. Cleaned idle air valve -- seems ok. Manually set idle with screw -- runs perfectly all conditions.

Customer (name blocked for privacy)

Status: Closed Value: $15

Have you driven more then 25 miles and reach speeds of over 35 MPH. If you haven't give it a try. When the battery went dead the computer rebooted. It doesn't remember the settings that it was at. To retrain drive for 25 miles at varing speeds and throttle settings. Including a couple of stops and then pulling off. Make sure you get it over 35MPH for some of the trip. If you have already been driving it and it still has the problem here is what to check. The ISC you have been checking is for the cruise control not idle settings. The idle air control motor is what controls the idle. take it out and clean the passages. Check the motor can you move the pintel in and out without alot of effort. If you can't replace the motor. Also check for a vaccum leak. Make sure PVC system isn't plugged. Hope this helps you out. Please accept my answer if your satisfied. Thanks 32dmadden

Reply to 32dmadden's Post: hi... thanks for the answer! I just returned from my 25 mile "reset trip" after cleaning the Idle Air Control Motor and putting everything back together. Everything is FINE now!!! Even the cruise control still works after having the wrong motor apart and in pieces :) Once the IAC was clean, it started right up and idled fine... but I did the break-in drive anyway with many stops, accelerations, slow and highway driving, etc. Didn't notice anything changing... just nice and steady and smooth all the way! Well, idle speed did seem a bit different at each stop, but not by a lot and it never tried to die out.

So, I think you for your help... it seems you hit the nail on the head this time! And you kept me from wasting tons more time playing with the WRONG motor (though it too controls TB setting). Oh, once I knew it was for cruise control, I turned cruise ON and sure enough the POWER pin jumped right up to 12+ volts :) I knew something had to power it... just didn't know it was for cruise :)

Your payment will be releases soon as I enter this. Thanks again!!

Russ

PS: I'm still seeing a trouble code of 12 even though I had the battery disconnected many times while working on this. I'll try disconnecting negative lead again and see if it goes away... but shouldn't it have gone already?

Edited by Customer (name blocked for privacy) on June 18 2006 at 7:29 PM

Code 12 indicates the battery has been disconnected. It will disappear in 50 ignition key cycles. Thanks for the accept. I'll be around if you need me. 32dmadden

Reply to 32dmadden's Post: Thanks!

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