1996 Dodge grand caravan 3.3L. Interchangeable pcms?

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Old 06-19-11, 08:00 PM
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1996 Dodge grand caravan 3.3L. Interchangeable pcms?

Confirmed on here that my PCM is faulty. What is interchangeable with my 1996 FWD 3.3L Dodge grand caravan manufactured 5/96?
 
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Old 06-19-11, 08:17 PM
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Confirmed where? By who? What is the problem with the PCM? Swapping in used parts isnt real safe practice. If you by chance get a controller that was used on a vehicle with security on yours then it could cause a no start and possibly cause problems with the Body controller on your vehicle. I can promise you that you do not want to buy a new PCM AND a new BCM. I just recently did them together on a 1996 or 1997 model and the BCM alone was over $800. If you purchase a PCM new it will have to be programmed to your vehicle. They come prett much blank so software has to be added based on VIN number.
Hope this helps ya,
Billy
 
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Old 06-21-11, 08:39 AM
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Some one on here had the exact same problem as I am having. I had already trouble shot it, but found on here that it was the PCM that fixed his prob. I don't want to spend the $400 for a new one and all the junk yards don't have my specific PCM. I was hoping that another PCM from a different year or model might work. I guess I will just have to get the new one. Thanks for your reply you are right, I don't want to buy a BCM.
 
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Old 06-22-11, 04:48 AM
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What is the problem with your particular vehicle? Alot of PCM's are replaced for no apparent reason. They get condemned pretty easily and its a pretty expensive guess.
 
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Old 06-22-11, 08:08 PM
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You are right that is an expensive guess, and that is why the first thing I did, after I couldn't get it to start, is buy a book for it. After checking the connections, and the coil and finding it to be in specs, I checked the coil driver circuit and found that the blue/tan (#2 and 5 cylinders) wire stayed grounded while cranking. I disconnected that wire then it started and I drove it home on 4 cylinders.

Today I found a used PCM from a junk yard from the same vehicle make, model, and year and even has the same # as mine. I plugged it in and didn't start, checked the driver circuits and found the grey/red (#1 and 4 cylinders) wire to be constantly grounded while cranking, so I unplugged that wire and it ran on the other 4 cylinders.

2 PCM's, 2 circuits, same problem. Hmmmmm......???
 
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Old 06-23-11, 09:27 AM
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When you find this ground on these driver wires what are you seeing on the other driver wires? Where are you testing this circuit? At the coil or at the PCM?
 
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Old 06-24-11, 10:20 PM
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The other wires are fine. I checked them at the coil, then with the pcm unplugged I checked them to see if any where grounded or shorting and all is fine. I'm starting to think I just need to buy a new PCM.

So here is how I checked the wires: Connected test light to positive term of battery then with the circuit unplugged from the coil I probed each wire (3) while my son cranked the engine. 2 of three flashed the test light and the bad one stayed light. As stated above Blue/Tan (#2 &5 cylinders) stayed light while cranking with the first PCM and grey/red (1 & 4) steady light with second PCM. With the bad wire unplugged on each PCM the engine will run on the other 4 cylinders.

With the circuit unplugged at both ends I used my ohm meter and found every circuit to be open with any other wire and ground.

If I'm doing something wrong or missing some thing please let me in on it.
 
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Old 06-25-11, 02:56 PM
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It sounds like you are testing everything correctly. It is odd that you have 2 pcms with similar issues, but hey it does happen. And since it is a different circuit then it is quite possible that the "new" PCM is also bad. The driver being constantly grounded by the PCM may be shorting the coil pack so that it will not run. Ive never seen this but its always possible.
I think a new PCM is in order.
Billy
 
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Old 06-26-11, 09:40 AM
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Thank you Billy,

It's always nice to have a second on an expensive decision. Now my question is: Does the new PCM have to be programed? I found one on ebay for $150 free shipping that the description says plug and play, doesn't need programed, but when I called the shop they told me that even a used one has to be programed. Of coarse I know the used one didn't have to be because I ran it on 4 cylinders.
 
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Old 06-26-11, 12:04 PM
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Yes it will need to be flashed to your vehicle just as it was on the assembly line when it was built. A dealer can do that with your VIN number, and also provide any updates to the software since it was built.
 
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Old 06-26-11, 07:42 PM
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On a vehicle of that vintage the vin and pinion factor will need to be programmed into a generic pcm with basic software. A new pcm will need to be programmed with vin specific information as they are normally blank. The reason that the used one worked like it did is because it had already been programmed to a vehicle.
 
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Old 07-17-11, 09:56 AM
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Thanks for the help. I got another PCM from another vehicle that the #'s (on the PCM) didn't match and it's running like it's supposed to now. Thanks again appreciate your help.
 
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