Anyone ever open and repair a TCM?

[TOBASH]

I picked up a spare TCM and case. Before ordering the new module I was wondering if anyone had ever opened one up and attempted a repair.

I have no idea what will be inside, but I assume a chip to accept EEPROM and some other electrics and probably water damage.

 

[Retiredwarhorses]

I picked up a spare TCM and case. Before ordering the new module I was wondering if anyone had ever opened one up and attempted a repair.

I have no idea what will be inside, but I assume a chip to accept EEPROM and some other electrics and probably water damage.

heres a novel concept…open it

 

[Mogman]

The issue as with many electronic boards is finding the documentation and then building a test jig to simulate every input and output to verify problems/operation, which would be the "correct" way to do it.

The board is not potted so one can simply clean and look for burned and defective components (visual) and testing with a meter all components that can be identified.
One problem you may have is if you find a burned component is first to identify it then figuring out without a schematic what likely lead to its destruction.

I have successfully repaired many "mystery" boards over the years this way, sometimes it's as simple as finding a bad solder joint.

The "re-manufactured" modules are pretty cheap so investing allot of time does not make much sense.

 

[TOBASH]

heres a novel concept…open it

Steve, my friend… Before opening it I figure asking around is never a bad idea. Why reinvent the wheel?

 

[Westo]

I had a problem with mine and opened it up. Mine had a burnt up capacitor on it. I was originally thinking about repairing it (especially when I thought a new TCM was $800) but there were no markings on the capacitor to indicate what part I should look for to replace it with, so I just got a new one.

 

[Retiredwarhorses]

Steve, my friend… Before opening it I figure asking around is never a bad idea. Why reinvent the wheel?

the casing is meant to opened and serviced, the TCM itself “the older GM version” is meant to be upgraded…live a bit dangerously and bust out your screw driver.

 

[TOBASH]

Opened it up.

How the heck does water get into such a heavily protected unit!!! And why not place packaging tablets to absorb/ scavenge the water?

One small doo-dad fell free. 1x2 mm. I can ID the spot but not the purpose.

I will wash in deionized water in the future and see if anything becomes more clear.

In the mean time I will treat this as toast and I will need to purchase a new one. I guess I will need someone to suggest a source.

TIA

T

 

[DREDnot]

That unit is toast.
The whole box is just a "waterproof" faraday cage for a stock GM TCM. I believe there are multiple part number TCMs that need to match your particular year(?) of transmission.

 

[TOBASH]

This was purchased as a spare. I want to carry a spare box.

The magic green smoke exited this TCM a long time ago.

 

[DREDnot]

This was purchased as a spare. I want to carry a spare box.

I assume you mean a spare TCM (mounted in the big box) If so, open your unit and get the part number off it so you get the correct one

 

[Retiredwarhorses]

Opened it up.

How the heck does water get into such a heavily protected unit!!! And why not place packaging tablets to absorb/ scavenge the water?

One small doo-dad fell free. 1x2 mm. I can ID the spot but not the purpose.

I will wash in deionized water in the future and see if anything becomes more clear.

In the mean time I will treat this as toast and I will need to purchase a new one. I guess I will need someone to suggest a source.

TIA

T

Me thinks its from condensation build up, I’ve had a few that have been wet inside, the truck would literally have to be under water for quite some time with some of the water I’ve seen from inside some I’ve had here in the shop.
That’s also the later model TCM from PCS, I prefer the shift pattern on the older TCM with the CZSU EPROMM.

 

[TOBASH]

I assume you mean a spare TCM (mounted in the big box) If so, open your unit and get the part number off it so you get the correct one

Agreed. I also have purchased a separate manual controller that will essentially turn this into a four-speed manual transmission, so if I am out on the road in the middle of nowhere, I will be able to get home safely and effectively using all four gears and overdrive.

 

[TOBASH]

Me thinks its from condensation build up, I’ve had a few that have been wet inside, the truck would literally have to be under water for quite some time with some of the water I’ve seen from inside some I’ve had here in the shop.
That’s also the later model TCM from PCS, I prefer the shift pattern on the older TCM with the CZSU EPROMM.

Steve, your knowledge base is amazing and you never cease to impress. Thank you.

 

[Retiredwarhorses]

Agreed. I also have purchased a separate manual controller that will essentially turn this into a four-speed manual transmission, so if I am out on the road in the middle of nowhere, I will be able to get home safely and effectively using all four gears and overdrive.

the transmission all electronic, you can’t Make it manual, unless you have a manual valve body, the 1-2 3-4 are solenoid operated, those shift commands come from the TCM, if the TCM tanks….your in limp mode.

 

[TOBASH]

the transmission all electronic, you can’t Make it manual, unless you have a manual valve body, the 1-2 3-4 are solenoid operated, those shift commands come from the TCM, if the TCM tanks….your in limp mode.

Needed some plug adaptations.

 

[Mogman]

You can buy a reman TCM and you will need to get an EPROM as the PCS does not have one, Eastern Surplus has them pretty cheap

 

[patracy]

I have seen worse PCB's repaired. But it's only when the ability to replace the entire PCB isn't an option and parts are obsolete. (I am into retro computers, so there's a lot of cannibalizing and reviving old computers) But that stuff is typically only two layer PCBs. That's relatively new enough to be up to a 4 layer board. It certainly has vias for 2 at least. It's hard to make out, but it might be a 3 or 4 layer board. So that makes things even more complicated to repair. The first thing to repair something like this would be to put it in a ultrasonic cleaner. Then break out the magnifying glasses to check for any top layer breaks. When a trace is broken, you can repair it with a bodge/flying lead. Or sometimes simply scraping off the insulator and bridging the break can work.

Looking at the board, it's mainly passive components. The TLE6220GP is what's driving the solenoids in the transmission. The rub is the firmware in that CPLD, PCS doesn't appear to have released the 2100 schematic. So it's also unlikely you'll get a copy of their firmware either. It has a JTAG header on it. But I'd also bet they have the security bit set to it. The only way you'd get the firmware is to try to glitch it and dump the firmware from it. (And that's a maybe)

Could it be repaired? Sure. Would it be cost effective? Not a chance. Would it be fast? Also not a chance. Would it work? A slim chance.

I'd imagine that *some could be repaired. I bet the 6220 drivers go out on them a lot or other passives. But when it comes to any of their "proprietary" IP, you're most likely not going to fix it.