Transmission control module replacement, does it need to be reprogrammed?

The module needs to have the following done to it, once it's installed. (from OE service info)
Quick Learn Procedure - Allows the transmission control module to learn the characteristics of the vehicle
Electronic Pinion Factor Procedure - Reprograms the TCM to compensate for different tire sizes and final drive ratios on 1993 and newer vehicles.
Now if you give them that information, they might be able to program it prior to you getting it. Hard to say for sure as I've heard of some being preprogrammed.
It's not a hard item to change, remove the negative battery cable, then unbolt the connector on the front, then remove the mounting bolts and take it out, reverse the process for the new module.

Well online they say they are plug and play and don’t need to be programmed.

That would be if they had already programmed it using your vehicle information. I don't use those types myself, so I'm used to the OE process of using the adapter cable to do the pinion factor and the relearn.

Okay, but what I’m saying is O'Reilly's says that it’s plug and play, and no programming is required.

It is if they programmed it. It is not if they didn't. I suspect they are programming it in advance because the 3.3 in the Caravans were pretty much all the same. Then you plug it in, and it starts learning your vehicle.

Hi guys. Let me try to clarify this. By "plug and play", they mean you can just plug in the replacement module, and it will operate properly with no reprogramming of any kind. The transmission will shift properly, and the module will communicate with the other modules like normal.

One of the many "customer-unfriendly business practices" that GM is famous for is they started with some 2002 truck models that had to have the vehicle ID number programmed into a replacement module, and of course, only the dealer could do that. Independent shops could buy a new module from the dealer, and install it, but then they had to take the vehicle to the dealer to have the module programmed to that vehicle. Whatever GM dreams up to separate you from your money, other manufacturers copy a few years later. This also makes most salvage yard modules worthless.

Chrysler approached this differently. They use a four-digit PIN that has to be programmed into a replacement module. The dealer I used to work for looked one of those up for a friend and gave him that number over the phone. Later, they looked up those numbers for two of my vehicles, all at no charge. Steve recommended a very nice aftermarket scanner a few years ago. I bought one and was able to enter the PIN in two modules, both on a 2015 Ram. The procedure took the better part of 30 seconds.

Unlike with GM's procedure that allows a module to work on only one vehicle, with that Ram, it appears up to three PINs can be entered, so that module can work in all three vehicles, and it looks like old, unneeded PINs can be removed so the module can be used in still more vehicles.

FARR2007, THAT is the programming you do not have to worry about. On those newer vehicles, replacement modules do not work, and usually won't even "wake up" and turn on.

The programming Steve is referring to can be considered "adjustments". Your replacement Transmission Computer is going to operate as soon as you install it, but it's going to function based on the vehicle it came out of. Most notably, there could be two or more optional "final drive" gear ratios that were available, similar to the gear ratio of a rear-wheel-drive differential. We used to install a speedometer drive gear with a different number of teeth when we replaced the rear axle with one with a different gear ratio. On your vehicle, that is changed, or "programmed", by selecting the correct final drive gear ratio, (pinion factor), from a drop-down menu on the scanner's screen. If the wrong pinion factor is in the module now, the speedometer will show the wrong speed.

Similarly, the older Caravans were available from the factory with 14" or 15" wheels. Those with 15" wheels came with larger brakes, and usually a larger tire outer circumference. You can't interchange wheel sizes, but you can buy larger tires to fit your wheels. If you do that, you have to enter that into the module, also from a drop-down menu on the scanner. If the van the module came from had a different tire size than what you have, again, the speedometer will be off.

There are other "customer preference" adjustments that are programmed into the computers. For example, a common one used to be speed-sensitive door locks. If that is programmed on, the doors lock automatically at 15 mph. Some owners don't like that feature, so it can be programmed off, but you need a scanner that can do that. That is a setting in the Body Computer.

The "learning" Steve mentioned is nothing to get excited about. In one of your other posts, I made reference to the "clutch volume index", (CVI). That's a set of four numbers indicating the volume of transmission fluid it takes to apply each of the four clutch packs. By looking at those, a transmission specialist can tell you roughly the amount of life left in the transmission. If the clutch plates in the previous van were worn a lot, it takes more fluid for a clutch pack to lock up. The computer learns that and will apply third gear, for example, a little early, and wait is little longer to release second gear. The extra overlap produces a nice crisp, like-new" shift feel, but again, that is due to those learned values. If the clutch plates in your van have little wear, that overlap can cause a harsh, or really solid up-shift at first. A replacement computer learns the need to compensate for much-worn clutches very quickly, as in two miles or a dozen shift cycles. Learning to compensate less if your clutch plates have little wear won't be a concern because the CVI numbers are lost from memory when the battery or module are disconnected. That learning when you first start to drive with the new module is a form of the programming Steve referred to. Many scanners today have a "quick-learn" feature that allows mechanics to perform that relearn in the shop without needing a test-drive. It's simply a time saver and doesn't have to be done by the mechanic. The van will do that itself.

My experience has been to notice nothing different when replacing a Transmission Computer. We start with a test drive to be sure everything is working and the problem is solved, then we use the scanner to check or change the pinion factor and tire size. If you buy a remanufactured module from the dealer, they come with the most common or most popular options already programmed in, so quite often you don't have to change anything. Just plug it in and go.

To boil this all down and simplify it even more, install the replacement module and go for a test drive. Have someone pace you with a second vehicle so you can compare your speedometer readings. If it's correct, you're done. If it reads high or low, you'll need a scanner to select the correct tire size or pinion factor.

So I should just be able to install this new TCM without any programming, is that correct?

Transmission control module location needed.

The TCM is located at the right side of the firewall, check out the images (below). Let us know if you need anything else.

If I replace the TCM will I need to have programming done because online it says just plug and play no programming required.

That is correct, it is plug and play, once it is installed give it time to relearn which can be done by driving it around for a few miles. Let me know how it goes.

Okay, because I have been told differently by someone else, so you're saying I don’t have to have it programmed, right?

Yes that's right" like ken was saying its plug and play. it will need to be driven through what's called a drive cycle which is varied on different vehicles but i think the drive cycle is about 15 mils on this vehicle and the ECU will automatically reset and you should be good to go. good luck

It may be plug and play, I would think that they set them with the most common tire size and gear ratio for the Caravan. The rest it learns as you drive. However, if you get one that is set for 14-inch wheels but you have 15 inch you will see that the speedometer is wrong. The same goes for the pinion factor, which is the final drive ratio, there are at least three different ratios that I know of. It would also show up as a speedometer error and possibly the shift points would be slightly off. Yes, you can plug it in, and have it work, but it may not actually be correct if those settings are different than the way your van was built. If the place you buy it from asks you for the tire size, year, model, engine or the VIN when you order it, they likely look those up and set the module up based on that data.

Think of a new laptop computer. You unpack it, plug it in, turn it on, and it works. You're done. Now, if you decide you want to make the display brighter, you program it to do that. Same with the volume. That is what they mean by "programming" the replacement Transmission Computer. It is going to work as soon as you plug it in. Period. Later, if you find it needs an adjustment, you use a scanner to program in that adjustment. If the donor van had the same tire circumference and the same pinion factor as your van, you're really done. No adjustments will be necessary.

If you still don't believe us, at least just plug it in and see what happens, then we'll go from there.

What if the transmission does need adjustment, because reason I’m replacing the TCM is it keeps going into limp mode and won’t shift, I already replaced the solenoid pack and the two speed sensors on transmission.

Okay, well the reason I’m replacing the TCM is it keeps going into limp Mode and won’t shift and also it runs poorly, I already replaced the solenoid pack and both speed sensors on the transmission.

I didn't mean to stick my nose in an ongoing conversation. I've been following along to learn the solution so I can add that to my memory banks. My previous comment from a couple of days ago was to clear up the confusion about programming to help you get to the solution sooner.

That said, once your system went into limp mode, there is going to be at least one diagnostic fault code stored in the Transmission Computer. That code needs to be read and recorded as the starting point in the diagnosis. Chrysler made reading engine fault codes much easier to do yourself than any other manufacturer, but for codes in the Transmission Computer, you need a scanner or one of the newer simple code readers that can access the Transmission Computer. I'm not up on the latest code readers, but I know there are some that can talk to the Anti-lock Brake and Air Bag Computers. For most people, buying a scanner is not a good value unless you will have plenty of need for it. Instead, visit any shop with a scanner old enough to work on '95 and older models. Be sure to write down the exact fault code numbers. They will have two digits. If their equipment provides a description of the code, still write down the numbers as those descriptions can vary in interpretation sometimes.

If you've recently had the computer or the battery disconnected, any fault codes will have been erased. Then you just need to drive the van until the problem occurs again. At that point the code will stay in memory until you have it read, even when you restart the engine to get it out of limp mode. The tire size and pinion factor we keep talking about does not get erased from memory when the battery is disconnected.

Steve or any of the other experts will be able to determine the best way to continue once they know the fault code number(s). The computer itself is usually way down toward the bottom of the list of suspects, as failures aren't real common. In your other post, I described the clutch volume index, (CVI) numbers used to determine the amount of life remaining in each of the four clutch packs. I also described how this computer learns, or compensates for worn clutch plates by adjusting when a clutch pack applies or releases during shifts to keep the feel of the shift nice and solid, but as one or more of those CVI numbers reaches its maximum, the computer can't update any further. That's when you can get the characteristic "engine runaway" we used to observe decades ago telling us a rebuild was in our future. With this transmission, it will never get to where you experience that "runaway" Long before it gets that bad, the computer detects the small increase in time the slippage occurs between gears. When that is considered to be too much time, it sets a fault code for "gear ratio error". In simple terms that means in a certain gear, at a certain engine speed, there is supposed to be a corresponding tire speed. When the engine speeds up during the shift, the computer sees that slippage. This is where looking at the CVI numbers can verify the diagnosis of worn clutch plates.

That's just one example of what the fault codes can tell us. Slipping clutch packs only show up while you're driving, so you start out normal, then bang down to limp mode when on the road. The computer also performs electrical tests on the shift solenoids, pressure sensors, and temperature sensors. Those tests begin as soon as you turn on the ignition switch. If an electrical defect is detected, the system goes into limp mode as soon as you shift out of "park". You'll still have "park, "reverse", and "neutral", but only second gear going forward.

I found this chart that shows all the things the computer can detect, along with the possible causes. I have four Caravans / Voyagers, including a '94, so I saved a copy of this chart for my use later. If you find it's too hard to read, first try to copy and paste it into a typing program like MS Word, where it can be expanded. That's where I prepare and format them.
If that doesn't work, I can split it into parts that can be expanded, then repost them for you that way.

I hope that helps. I'll go sit in the corner now until you guys need more of my wondrous wisdom.

So I am wanting to replace the Tcm because it keeps putting my car in limp mode and won’t shift, I have already replaced the solenoid pack and the two speed sensors on the transmission, however I did notice two more sensors on the transmission at which I don’t know what they are for and which I can’t get out because I don’t have the right socket or not sure what I need or if they need to be replaced, the car also runs badly sometimes or dies, everything I’ve researched points to a faulty Tcm
As if I do the key dance reset it will shift normal again

You're adding to your confusion by starting multiple new questions. The "key dance" you referred to is only for fault codes in the Engine Computer, not the Transmission Computer or any of the other computers. You need a scanner for those other computers, or at least a code reader that specifies it can access Transmission Computers.

Okay, with it going into limp mode and running badly, that could be the TCM but it's not real likely, as Doc says they are not really failure prone. From the sounds of it you need to find a shop that has an OBD I scan tool, that will actually pull the TCM codes to give you an idea where to look. A scan tool like the old Snap On MT2500 (the brick) or an OTC Genisys with the OBD I software and adapter plug. Some of the new tools claim to work with it as well, but I've only tested a couple. The connector for the system is an odd shaped 6 pin connector under the hood. Because it's OBDI most of the places that do free scans won't touch it, because it requires the older tools, or the special adapters. Find a place that can scan it and use the chart Doc provided to see if it is the TCM.

But do I have a problem with my TCM? And what other computers?

So is my TCM bad and what other computers?

That is why you need to have it scanned; there is no way to know what is wrong at this point. Without looking at all the module information and any stored codes to see what the system is actually seeing as problems; you could replace every piece and still have the problem because it is something else. The TCM in that car controls the Transmission, it isn't going to cause the engine to run bad unless it is shorting out something else. However, a bad running engine could cause limp mode and shifting issues. That is why you need to find a scan tool that will work on that van and go from there.

What type of scan tool do I need?

Because it's a 94 you need one that can read the OBD version 1 codes and data. The ones for modern vehicles usually won't work unless they have adapters and the correct software. The 2 most popular aftermarket tools are the ones I mentioned earlier. The Snap-on MT2500 with Chrysler cartridge and the Genisys . There were others but those are the easier ones to find. There was also the Chrysler DRB II factory tool but those are harder to find in working condition. My Launch and Autel units both came with the adapters for OBDI but I've never used them as those are very rare vehicles where I am so I can't say how good they work on vintage vehicles.

You're demanding your doctor diagnose what's ailing you over the phone, but you refuse to go see him. The fault codes were designed to tell you in which circuit or system to start looking, otherwise everything is just a guess. That's the most expensive and least effective way to diagnose this problem.

If you're anywhere near northern Wisconsin, I would be happy to read the codes for you, but since they throw a pound of salt on an ounce of snow here, there aren't many '94 models, other than mine, running around. Another alternative to consider is to find a nearby community college with an Automotive program and talk with an instructor. We were always looking for live work to give our kids real-world learning experiences. The only possible drawback is we would only do this type of work when my Electrical class, or the other instructor's Engine Performance class were being taught. To try to do this during, say, Brakes class would take work away from the shops that hired our graduates, so we had to stick to the subjects currently being taught. It takes longer to dig out and connect the scanner than it does to actually read the codes. Within a couple of minutes we'll have an idea of how to proceed.

If you insist on replacing the Transmission Computer, look for a pick-your-own-parts salvage yard. In particular, I've been to 16 of "Pull-A-Part's" yards. They're all very clean and well-organized, parts are inexpensive, and employees and other customers have always been very friendly and helpful. You can do an internet search to see if there's a yard near you, and if they have a similar model in the yard. I bought a used Engine Computer for my '88 Grand Caravan a few years ago for only $25.00. There's a lot of similar yards popping up all over, but none are as clean as those at Pull-A-Part.

If you install a different computer and it continues to go into limp mode, it's doing what it's supposed to do. Then you'll be forced to have the fault codes read to know where to start the diagnosis.