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I hope you'll share the conclusion to this story when it happens. Until then, Good luck.
 

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Just checking in. Did you get home, at least?
 

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Discussion Starter · #24 ·
Yes, I drove it home (1066 miles) at 30-35 mph on county, country, city and state highways, about 26-28 hours in all towing a u-haul trailer but I made it.
 

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Discussion Starter · #25 ·
I have a 07' Grand Caravan in pristine condition and I plan to swap both the ECM and the TCM and see if that cures the problem. I have always questioned the quality of their computers.
 

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I have a 07' Grand Caravan in pristine condition and I plan to swap both the ECM and the TCM and see if that cures the problem. I have always questioned the quality of their computers.
You're not going to get far. Your 02 has a separate PCM and TCM. That 07 has the NGC controller and the PCM & TCM are integrated into one box. The PCM is in front of the battery in both cases. You'll be able to see that the 02 has two connectors going to it and the 07 has four.
 

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Discussion Starter · #27 ·
I took the van to AAMCO here in Indianapolis and they had it for a week or so, they consulted with AAMCO in Florida on what had already been done and then they called me and said they knew of nothing more that they could do, but they knew the problem was electrical and suggested a shop near here that specializes in electrical problems but that's just more money down the drain.
So I'm going to have to figure it out myself.
 

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I would think it's their obligation to pay the bill from the next shop. Can you talk to somebody like the BBB to get them to take responsibility for this?
 

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Discussion Starter · #29 ·
First off I'm trying to find the correct part number for the transmission wiring harness for a Dodge Grand Caravan, Sport with a 3.3 litre engine. My thinking is if I replace it with a new one that, that will remove all doubt about the wiring being the problem.

Replacing the ECM, TCM and Shift solenoid valve assembly has not changed a thing and if the wiring harness doesn't fix it, what else is left? Remember, codes P0750 and P0700.
I'm also trying to make sure I have the correct wiring diagram for it.

I've already got way too much money wrapped up in it to just junk it and it's in excellent shape otherwise.
Yes, I drove it home (1066 miles) at 30-35 mph on county, country, city and state highways, about 26-28 hours in all towing a u-haul trailer but I made it.
Can my ECM and TCM be tested to prove there good or bad?
 

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4869530AH is the part number I found for your wiring harness. It also came with a price tag of $1507.50 at one of my nearest dealerships and that doesn't even include the injector sub harness for another $273.75. That online price tends to jump up once you go ask them what they really want for it at the parts counter. If you want to DM me your VIN, I'd like to double check that part number against said VIN. While I was at it, I got the OE part number for the solenoid pack: 5140429AA and it's $170.25. This is not the place to buy parts on wild guesses.

As far as testing other stuff to verify PCM and TCM faults, all the voltage drop testing & wiring diagrams I documented weeks ago stands as how you prove what is or isn't good. I found and added the OE wiring diagram and it looks like everything lines up with the Mitchell diagram I posted earlier.

If you can and want to drag that thing up to Madison, Wisconsin with it, I'd be happy to take a look at it personally if we can make our individual schedules work. It comes with a few rules: 1 - Don't tell me how to do my job. 2 - You understand that I'm giving my time for free and while I'm confident in my ability to diagnosis this, I can't guarantee anything; which brings us to 3 - I'm imdemnified from any liabilities to you or the vehicle. It's not that I'm trying to be a dick, but I do prefer my good deeds go unpunished once in a while. Send me a DM and we'll see if we can make something work.
 

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Discussion Starter · #31 ·
This is the Vin # 2B4GP44R92R663101

Yeah those prices are out of line with the real world, I've found some of them on eBay a lot cheaper.
 

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The part numbers I found are good.
 

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Discussion Starter · #34 ·
A friend of mine is telling me that his wife's car, a Chrysler something or other, was having transmission shifting problems similar to mine and a friend of his teaches OBD-2 and DTC-2 troubleshooting at a local community college near him and he checked the car out and found the ignition switch wiring, not the switch itself was causing the problem.
Is this even possible? It doesn't even seem credible.
 

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A friend of mine is telling me that his wife's car, a Chrysler something or other, was having transmission shifting problems similar to mine and a friend of his teaches OBD-2 and DTC-2 troubleshooting at a local community college near him and he checked the car out and found the ignition switch wiring, not the switch itself was causing the problem.
Is this even possible? It doesn't even seem credible.
The Chrysler something or other was similar, but there's no way to guarantee it's the same problem. Given the really vague descriptors you're providing, it's likely still not an apples to apples comparison. As far as feasibility of an ignition switch or wiring goes, it is decidedly possible. Your van does have a start sense/signal circuit from the igniton switch to the TCM. I'd assume it's going to be a "wake up" circuit. For that to be rational, though, I'd have to assume that there was a different code at play for the Chrysler something or other for no communication with the TCM. The symptom is the same between your van and the something or other. You've got second gear only. The difference, in my mind, would be that her TCM wasn't getting powered up and stays in second by default whereas your TCM is getting powered up and forcing the van to stay in second. For any of that to hold water, I'd need specific and accurate information on the other car. What's the actual model & year; what are the actual codes, and so forth. I'm not interested in diagnosing a car that's already fixed though.

I start a new job on June first. My calendar is open until then. It would be awesome if you could find a way to drag that thing to Madison.
 

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Discussion Starter · #36 ·
Forget about the Chyrsler, I shouldn't have mentioned it.

I have been trying to find a suitable vehicle to tow it to Madison with no luck, so I will have to drive it as is. It looks like I can leave here sometime Monday afternoon 5-24-21 and take the off Interstate route which should get me there sometime Tuesday. How do I contact you when/if I get there?
My number is 317-491-7267
 

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I sent you a text to that number.
 

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Flightsimmer'02 brought the van to me and after I got it fixed, he asked me to share said fix and some insight into my process to diagnose it. The short answer for the fix is I found a break in two of the wires going to the solenoid pack. One was the main power wire to the solenoid pack and the other was the TCM control wire for the OD solenoid. The insulation broke open on both of them inside the primary harness about halfway between the solenoid pack and the TCM. They eventually became overgrown with green crusty oxidation and caused a voltage drop. I'm going to save the diag write up for another post. The way I write about stuff like this walks a dangerous line between being thorough or verbose. In the meantime, here's a crappy pic that looked much better on my phone. Ironically, you're looking for the green fuzzy spots on the wires.

630149
 
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This small book I'm about to write is largely intended for eyes in a specific transmission shop in Florida. Since I'm leaving this in a very public forum, you're welcome to read into this yourself, whoever you are, and I'll try to explain a few things for those not participating directly in this.

Mr. D brought me this van from Indiana to Wisconsin last Tuesday morning still stuck in limp mode and second gear. When I got it; it still had the same two codes he left Florida with: P0700 and P0750. P0700 is a generic code and P0750 is for a low/reverse solenoid circuit fault for those just starting to read into this.

I went into this not having all the service info I needed. I just had bits and pieces that I had tucked away from past repairs and a little bit of hijacked info from one of those so-called professional service repair websites. Consequently, I did have to do some testing just to understand if/when the TCM was going to activate the EATX relay. More on that later.

Using a wiring diagram as my main reference, I started my diagnosis by leaving the key on, engine off, and tested by back probing with my voltmeter for battery voltage (BV) on the DK GRN/WT wire directly at the TCM. I had no voltage there, so I went backwards to the solenoid pack and tested for BV on the YEL/ORG wire and still no voltage. Then I moved all the way back to the EATX relay and I checked for BV on the 30 and 86 terminals. (I managed to forget that the EATX relay is power side switched before this. Once I remembered it, I quit worrying about the 86 terminal and the control side of the relay for the time being.) I had BV at the terminal for 30 and installed a jumper wire from 30 to the 87 terminal. I went back down to the TCM and back probed the DK GRN/WT wire one more time and still 0 volts. I again moved up to the YEL/ORG wire at the solenoid pack and still no voltage. The TCM also has two YEL/ORG wires that get fed by the EATX relay and both of those wires did have BV all the way down to the TCM. At this point, I suspected I wasn't making good contact with my back probe at the solenoid pack. So, I pulled the connector and front probed it to find 2.44 volts at its YEL/ORG wire. This is the proof that there is a wiring problem, and the problem is a high resistance fault after the splice of all those YEL/ORG wires.

I wanted to prove that last statement to myself by finding a method to jumper power to the solenoid pack. (If I can make it shift with an alternate power source to the solenoid pack, I can feel better about having to open up the big chunk of the wiring harness.) I wasn't willing to cut up, pierce, or back probe any more factory wiring so as not to create new problems. I eventually wound up cutting & jumpering the power wire near the solenoid pack because I was still creating new problems for myself anyway. But now I'm running into another problem that isn't entirely self-induced.

The next big problem at that point was I couldn't verify when I should see power on the control circuit of the EATX relay. I had an inline relay tester with external pins for voltage testing. I never saw battery voltage on the 85 or 86 terminal under any circumstance. I wiped out codes and had a friend cycle the key for me a few times. I also had her start the car and put it in gear while holding a foot on the brake. My voltmeter never twitched. Naturally, I had become concerned I was dealing with two problems instead of one. However, the TCM caught every effort I made to bypass that relay. It kept the van stuck in limp mode and would flag a new code for improper voltage where the relay was removed or wherever I installed a jumper wire. This did, inadvertently, prove that there was no problem with the control side of the relay or the relay itself. The only code that would ever return was P0750 as long as the relay was installed and my jumper wire wasn't bypassing anything.

At this point, I still have one proven fault and there's nothing left to do but open up the harness. That is a messy job of cutting out what feels like a mile of the factory tape and dodging a couple pounds of sand & dirt that found its way into the harness over the years. To give myself some extra room, I pulled the LH headlight and the TCM to disconnect some circuits and free some harness anchors from the body so I can pull the primary harness down far enough to make a good repair. I found and fixed three wires. The two I mentioned in the last post and the GRN/WT wire that the other shop bypassed. Instead of just fixing wires at the point of the break, I cut out & replaced most of the length of each wire and crimp/sealed said wires a couple inches off each end to leave the original terminal in place at each connector.

I put it all back together and now the van is shifting, but it has a clunk in the 2-1 downshift and a new code P1775 - Solenoid Switch Latched In TCC Position. Luckily, the downshift fault resolved itself by the time I tried to show it to Mr. D in a test drive. I let him keep his van for a while to get lunch while I ran off to borrow a better scan tool. When we met up again, he had no complaints about how it drove and by the time I plugged the scan tool into it, the TCM had already erased the P1775 from memory by itself. We went for one more drive around town and told Mr. D his van was ready for happy trails at highway speeds that afternoon.

If anybody at AAMCO in Venice, Florida reads this directly, I want to voice a few complaints directly to you. It's my understanding that you replaced the PCM more than once. The PCM was somewhere between a highly improbable to a completely irrelevant component in this diagnosis. That should have been obvious by the time you traced out the circuit path for the low/reverse solenoid. You guys put the bypass into the GRN/WT wire. This wouldn't have been overly upsetting normally; but you left the bypass wire just hanging loose in the wind. That wire should have been, at minimum, zip tied to the harness to prevent it from rubbing on sharp edges. I also noticed the dust cover for the TCM connector is missing. That TCM is closer to the elements than most modules and they're more vulnerable for it. When next that van sees winter, the TCM and its connector will get doused in winter slush mixed with road salt. I'm sure this was frustrating for you guys and I do understand how easy it is for mistakes to happen when you've got a vehicle kicking your ass for days at a time, but so much of what you didn't do right has potential to lead to larger problems that take time to happen. In a way, Mr. D could wind up paying for this diag and repair twice.

My understanding is Mr. D was basically stranded for two and a half months and he paid at least $1150 for ineffective repairs. If there has been no refund of any sort issued, I think some money is due to be refunded to Mr. D. It would appear his old PCM has been reinstalled and Mr. D said it looks to be the original to him as well. The solenoid pack does look new and I believe the TCM is a salvage yard part. Assuming no money has been refunded to this point, I'd like to see Mr. D refunded the entire amount of labor billed to him and his billed part cost be reduced to what your cost on the part was. Basically, I'm asking you to keep enough money to pay your cost for the parts that are still sitting in Mr. D's Caravan and you refund every other cent back to him.

Despite my frustrations with you at AAMCO, Mr. D still speaks well of the people in your shop. He appreciates your temperament and your demeanor. He believes you genuinely shared in the frustration of not being able to fix his vehicle. He's also asked that I offer some guidance to you guys. (He says you have more Caravans in line with similar problems.) I have no idea if you want said guidance, but I'll play along if you will.

Having said that, I really have to encourage as many of you as possible to relearn basic electrical principles and get acclimated to voltage drop testing. If any of you were schooled in things like flow charts and continuity testing, they're outdated and can be proven fundamentally misleading and flat out wrong. What's worse, is those flow charts can sometimes hinder your ability to think for yourself. Not to be egotistical, but my first three responses to this forum thread just about nailed the diagnosis back in the first week of April. It's those principles of voltage drop testing that got me there.

There is a guy on YouTube named Paul Danner and his channel is called Scanner Danner. He also has a website called scannerdanner.com . You can try to get what you can out of the free stuff he provides on YouTube, or you can buy a subscription for $11 a month at his website for complete lesson content and he's got his own book written to accompany his specific teaching. I think Paul can give you much better guidance than I can so you can eventually learn how to better think for yourself in your diagnostic strategy. He's got a lot more hands on experience and backs up what he teaches with real world diag and verified repairs. You'll need some kind of long-term approach if you can make time for it. If you've already watched everything on Netflix and Hulu by now, you can cancel one of those subscriptions and trade it for scannerdanner.com for a few months as you evolve into....You: god of diagnostics.

Assuming Mr. D was right and you do have a few more of those Caravans to diagnose with circuit faults, I'm also willing to work with you directly if/as time allows to diagnose one or two of them. I'll also try to help you get a little more acquainted with voltage drop testing along the way. If that sounds good, make yourself a log in for the Dodge talk forum and send me a direct message. Let me know if you're interested and we'll see what we can do from there.
 

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