Alright my DodgeForum.com friends. I have a simple question, with possibly the most complicated answers. I have done, literally, countless searches online about using a junkyard PCM. Some claim that you absolutely have to have it flashed, while others say, no you don't, it only affects the ABS, but everything else will work. I found a great deal on ebay..PCM for a 5.2, came out of a running 99 Durango, $80. Now yes, I can go get one from Take-A-Part when I go up there on Friday and they are $29.99 with a $3 core charge, so $32.99 plus tax. I am wanting to know...can I take an already flash unit, with a different VIN programmed in, and it work? Yes, I am taking a shot in the dark with an already USED pcm, that may have a ton of miles, and is original to the vehicle, but..my truck died in the McDonalds drive thru. It only does it when it's hot, and lets face it, underneath a Durango hood can be hot as hell. Poor placement(should be inside the cab), has lead to many a PCM death. I do believe I read something on here about the only information the PCM needs is the VIN because the dash cluster stores the mileage.

I do have a security alarm on my vehicle as well.. I found out by accident. My wife locked it up, and the actuator doesn't lock the drivers door..I opened the door..honk honk honk..I unplugged the battery, waited 10 minutes..locked all the doors, plugged the battery back in..it honked 3 times and shut the alarm off after I unlocked the door with the key. I do however notice that it doesn't flash...but did when I set the alarm off..

I'm sorry this if this reads confusing..trying to get all of this out of my head..gotta be up early, and sit through 3 1/2 hours of boring garbage...

 

the mileage in the PCM need to match the gauge cluster to within a certain tolerance in order for everything to work correctly, yes you need to flash your VIN to the module otherwise it will likely not communicate properly with other VIN locked modules in the truck.

in your case you also need to make sure that the PCM knows to look for the security system othewise the anti-theft device will shut the engine off very shortly after starting the truck, all of this is accomplished by buying a properly flashed unit

 

Agreed i would not waste my time with junkyard PCMs i would find a vendor that can sell you one already programed. you will be saving yourself alot of headache..

 

If it shuts down only when it gets hot it may be you coil getting hot and breaking down. Does it restart after it cools down?

 

Restarts perfectly...I thought about the possibility of the coil too. But if you tap on the PCM with a screw driver, it starts right up. I might as well replace the coil since its cheaper, see if I have the same issue...

Just to give you an idea of how long it runs as far as time goes. Drove it to Decatur, IN, which is about 15 miles...was in WalMart for hour or so, it started right up, drove home...About halfway there is a bridge that is being redone, and wait time at that light is around 5 minutes if you get there as the light changes to red. So total drive time, maybe 40 minutes..stopped in at McD's, 5 cars ahead of us in line..15 minutes of wait..as I went to pull forward, it died...so roughly an hour of mixed driving and idle time. Sometimes it fires right back up...other times it just cranks, cranks..no fire..tap on PCM, fires right up..half the reason I thought bad PCM at first

 

it could be a loose connection at the pcm or a bad wire there. when you tap it it might wiggle things just enough to make connection again. but the coil is cheaper the change so i would start there first.

 

I would disconnect the PCM and play with the plug. Maybe just corrosion and a few times disconnecting and reconnecting might make a better connection. Remember to pull the Neg battery cable off before disconnecting the PCM. This is the cheapest solution.

 

I just had almost identical problem a few weeks ago. I even built a heat shield/ bracket to keep pressure on the connections for the PCM. The heat shield/ bracket made it work a lot longer, but it still happened. I ended up just replacing the PCM and havent had the problem since.

 

This is what happened yesterday. I drove it around town to assess the damage from the storms that rolled through, it ran fine...about 2 hours later, I went to start it...crank..no fire. Had the wife come put..I pulled the plug closest to the windshield side(that's the plug with the broken clip teet)...tapped on the pcm...didn't start. So I pulled the plug again, and it started. I went to the junkyard yesterday and bought a hitch, and went to look at a 98 Durango I had pulled parts from previously. The plug I have to keep pulling to get it to start has a TON of electrical tape, not the factory style nylon tape it should have. I am debating on taking all that electrical tape off and seeing if it was spliced on..and redo it correctly if it was a cob job...