Just bought a 2002 Caravan with a computer problem! Experienced Dodge Computer tech wanted!

[mikefaster]

Hi, I am a mechanic and I know a lot about these Caravans... I am always buying them and fixing them up and keeping them for awile or selling them to make a little money...

My newest project, is a keeper... I had originally posted about trying to convert a 1998 4 cylinder caravan to overdrive, but I found this 2002 Caravan, which late in 2002, they started using overdrive, and then in 2003, they started using overdrive trannys in all the 4 cylinder Caravans... I "specialize" in the 96-2000 caravans, but the 2001-up are kind of like "New Ventures" for me...

I bought it as a non-runner for $500, so I was happy about the price, but it has 195,000 and it was off the road, sitting for a year, maybe 2; didn't get definite answers from the seller because the daughter was selling it for the parents... I was told that the computer was no good...

I hooked my scanner and it communicated, but I was only able to get 3 things with the "VIEW DATA" feature... (one) MIL STATUS, (one) ENGINE RPM, and (one) TPS RANGE...

That's IT!

Seems like I was ONLY viewing data from the Transmission computer because those 3 items are usually displayed twice, and then you can read the data from all the other items...

I tried to plug in a 1998 computer (same plugs and engine, but I know it's not right) just to see what would happen... It did NOTHING, but the scanner was UNABLE to communicate with the vehicle... I saw that as a good thing, because the car knows something is wrong as opposed to doing the exact same thing (just showing the 3 items on the View Data list...

Then I went to the junkyard and got the same part number computer from the same year and optioned car and it does what the 1998 Computer did, NOTHING, and UNABLE TO COMMUNICATE with the vehicle... So I still see this as a good thing...

So I sent my computer out to be reprogramnmed to MY VIN number and mileage, so I assume I am on the right path... Even if this doesn't solve my problem, when I do get it working, then I will have an updated computer, and I can sell the old computer for "something"... The computer costed me $75 and the reflash where I send it to costs me only $60 plus shipping both ways, so I am okay with spending that much...

My question is?

Should this work?
Should have I SUSPECTED the used computer to not work???

I have reflashed several computers, but they all ran and I was just looking for an updated computer...

I have also bought a computer on ebay and had it sent directly to the reprogrammer for a 1999 minivan (I bought a minivan WITHOUT a computer in that case-was sold off), but something tells me, it wasn't as necessary for the 1999 as it is for the 2002 (or 2001 and up vehicles)... I think I could have used the 1999 computer, used as it was, but I could be wrong... I DID use the transmission computer from the same year, similar vehicle WITHOUT getting it reflashed and I have SWAPPED many transmission computers from one van to another with different years with success... But NOT the engine computers...

PS- the fuses are good, the relays are good, fuel pump does NOT turn on, and nothing "computer wise" seems to work (of course)...

Thanks for your help...
Mike

[Cntrysthbst]

the main computer needs to be on the vehicle, and needs communication with the other onboard computers. the other computers you can flash but not the main one, it has to be programmed and after accepting the other 2, (bcm & trans), and related systems, then being in your year you'll need several software updates installed for it, our 2001 had this problem. the anti-theft is important to, it will not run if the computer isn't programmed to it, as in the "key" issue you had with it. when you buy a new computer they match part numbers but the computer still needs to be specifically programmed to that one vehicle. the 3rd generations are not as complex as the 4th's. we tried doing ourselves and simular method but ended up towing it to the dealer.

Is this true? i dont know, we learned all this at the dealer talking to the mechanic who only owned the caravans. seemed like a good guy. we believed him. anyways hope this helps...

[mikefaster]

Sounds right, it's just that I will never go to a dealer, so I am waiting for my computer to come back in the mail... The dealer by me wouldn't flash my last vehicle when I said the computer was the same part number, but just from another vehicle... They said the only way to do it was to buy a new computer for $$$, so I don't even thinking about asking them for anything... I know this way will be correct and be the correct computer; I'll just find out if it's the real problem when I get it back...

[mikefaster]

Well, computer is back in and reflashed, but it's doing the same... No communication, so I am thinking the Front Control Module, located on the fusebox... Anyone know how compatible the years are??? I'll be investigation this more...

Anyone with any ideas?

[jpb53]

Here's a diagram of the computer wiring. You can have any module on the buss cause a communication problem. One way would be to disconnect one module at a time and see if you can establish communications.

[mikefaster]

Okay, on the BLACK plug of the computer, wire number 20, had no power...

I jumped it with 12 volts and everything came alive and now I can "view data"... Then I turned the key, and IT STARTED!!!

I shut it off right away because I suspect bad gas and just wanted to finish the current problem...

QUESTION:

Is the ignition switch bad???

Or is it something else???

What gives #20 wire on the black plug it's power...

(I will be looking at the diagram from the last post)

[mikefaster]

I don't think that diagram helps me, being that I now know part of the problem...

Mike

[jpb53]

Attachment 41018

Attachment 41019

[mikefaster]

Do you have schematic for the plugs that are directly under the fuse box??? Seems like all the wires I have lead to under the fuse box...

Seems like ALL wires are good, NO breaks in them... Seems like the ignition switch is working, however pin number 2 goes to the BCM... Is it possible that the BCM is shutting down the PCM due to lack of proper resistance in the ignition switch at pin #2???

Any thoughts?

[jpb53]

I'm trying to help you and you seem to be jumping around here. When you refer to a pin # you do not confirm what the color and tracer are of the wire at that location. The 2 diagrams together in the 1 post show where the power is coming out of the ignition switch for start and run. You jumped pin #20 at the PCM and the computer powered up. You either have to start there and work back to the ignition switch or start at the ignition switch and wor to the PCM. The process is easier if you solve 1 problem at a time and don't get sidetracked.

[mikefaster]

I was just able to confirm that PIN #2 on the ignition is unrelated...

Basically ALL WIRES are good and have continuity... The pink/white wire at the #3 pin of the ignition switch ends up at the pink/gray wire at #20...

I am 99% sure there is something wrong with Power Distribution Center...

I am going to swap it from another van and see from there... In the end, I may just jump it because it is really easy to do, but there be other facets of the PDC that may not work or may be prone to breaking down...

I don't feel that I am jumping anywhere because everything I speak of is all related... The problem with the schematics, is that it doesn't show the separate plugs that go through the PDC... I "get it" though... It is supposed to be "straight through" power, just like the schematic said, but I was just thinking differently because the power travels through the 2 separate plugs under the PDC; it was getting a little confusing... I already had a few wiring diagrams from ALLDATA that someone gave me, and those were a little easier to read and they looked nothing like yours...

In all honesty, I figure most problems out on my own, but this is not my forte...

I will keep you posted if everything works out...

thanks for your help...
Mike

[mikefaster]

I thank you jpb53, as the second diagram did help me...

It wasn't the Power Distribution Center, the ignition switch, a fuse or any other "normal" thing...

Where #20 meets all the other circuits in the harness, there seems to be a place in the harness where 2 wires that are the same color, which is PINK/GRAY, come from the PDC and go down... They are supposed to BOTH have power... Only one had power and the one that did NOT have power was the wire in question... Chrysler has a habit of putting splices halfway down the harnesses... I had already taken apart half of the harness, so I didn't want to bother taken apart the rest... I simply had to jump the same colored PINK/GRAY wires together... I really made it a bigger deal than I needed to and this should work out fine...

I basically fixed it with a blue "quickie splice" connector worth about 2 cents...

I can show a pic of what I did, but it says I need a URL... Is there a way to inset an image directly from your computer on this site???

Otherwise, it's not bad buying a 2002 van for only $500 needing a 2 cent repair, LOL...

[jpb53]

Glad you got it fixed. Proper diag is by far more important than throwing parts at it as you proved with your repair. Yes splices can be a pain and you are far better off cutting them out and redoing the splice by solderig the wires and heat-shrinking the connection. Sorry but I have never tried to post a picture on this site.

[mikefaster]

Well a computer reflash is worth it and often overlooked... Many check engine lights and other computer "quirks" prove to be solved with a computer reflash... I will sell my old computer probably for what I paid for it, so it didn't cost me much... I only pay $60 for a reflash plus shipping both ways...

If I have a problem with the same circuit again, I'll know that I will have to rip apart the OTHER half of the harness and I will actually find the "spot" where the failure took place... LOL

I will keep this van for awhile, so if the problem comes back, it will happen to ME and I'll know where to look... Yeah, as you read above, I didn't splice it by way of soldering, LOL... 2 Cent "quickie splices" work well when pressed together properly(at least for now); I squeeze the metal into the wire and THEN I squeeze together the blue flap... And electrical tape in lieu of heat shrinking it, LOL...

Thanks again
Mike

[alexny1969]

... I only pay $60 for a reflash plus shipping both ways...

Can you tell where you had your computer reflashed?

Thanks!