GM TECH2 scan tool and OBD2TOOL seller

Mogman

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May 3, 2020
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Well the cheap scan tool evidently will not reset the TCCM on my 08 LMM, it looks like it should but when the reset button is pressed nothing happens, I have tried enough TCCM modules that I am confident it is not a bad TCCM and the vehicle was working fine before I pulled the TCCM to use as a donor for my HMMWV LMM project.
The best price I have found is around $250 from a company called OBD2TOOL, this would include a GM memory card, has anyone dealt with these folks and are there any "gotcha" items to look out for or any other advice? I figure it would cost at least $100 if I went to the dealer and NOT having to mess with those folks would be worth a least $100 so it looks like a wash for the most part and I would not have to repeat the whole thing with the dealer if this came up again.
THANKS!!!
 

TheBac

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Moved to Tool Crib.

There's a thread in this section concerning the clone Tech2s. You might want to browse it.
 
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Mogman

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I read through 10 pages of one thread and am more confused than ever, do I need a laptop? do I need a subscription? what is the 2007/2008 split in interoperability? the NANO looks interesting (and even cheaper), at least it is obvious a laptop is necessary but again am confused on what software I will need to reset the TCCM and where to get it.
 

dndj

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The 2007/2008 split in operability is likely referring to when GM began to transition away from the Tech 2 to their new PC-based GDS2 diagnostic package which interfaces to the vehicle with what they call an MDI module, using SAE J2534 interface standard. The full GM 5 year conversion window is available here as more and more models were changed over. GM GDS2 conversion timeline

The Tech 2 works fine as a standalone diagnostic tool, read/clear codes, ECM data like serial numbers/versions, monitor parameters realtime, etc. If you intend to flash ECM/TCM or other modules on the truck, you will need a subscription to GM's TIS2WEB service and a connection to a PC with GM's application installed. A bunch more info about that here. GM Techline Info System website

There's also something called Tech2Win, which is a piece of software that runs on a PC which emulates the functions of the Tech 2.
 
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Mogman

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I did see the Tech2win, I do not THINK I need to do a flash, I just need to reset or relearn the TCCM, on the scan tool I have now I can see the switch positions so the TCCM does at least can see what position the switch is in, but when I try to do a reset nothing happens, no motor activity at all.
I am not sure why the TCCM would "unlearn", I pulled the TCCM out of this truck and installed it in the HMMWV project and it works fine, before I pulled it I did a thorough job checking out the 1 ton so I am pretty dang sure there is no issue with the truck, and I have tried three replacement TCCMs in that truck, one was brand new in the package, maybe after a certain amount of time with no battery connected they lose their programming, makes no sense as the ECM and TCM do not.
 

dndj

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New TCCMs out of the box need to be flashed with a calibration for the truck.

My LB7 manuals nor does my Tech2 show any relearn procedure, so I can't be of much help, but I posted some pictures of the ATC (active transfer case - LOL) screens from my Tech2. There is one command available to directly drive the shift motor. I tried it, basically moves from one end (2H) to the other (4LO). Presumably this is a direct drive of the shift motor on the NVG263 (RPO NP1) without any other dependencies.

Regardless of all this, the learn procedure can be done on the LMM w/o a scan tool by holding the selector knob past 4L for 30 sec with the truck in neutral and key in ACCY position. Video


t1.jpgt2.jpgt3.jpg
 
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Mogman

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I watched the video, do not understand acc position, I only have three positions, off/lock, run and start, I do not have or cannot get to the normal accessory position and even if I did I could not get to it in neutral
 

Mogman

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OK I figured out where acc was and that WORKED, YOU ARE MY HERO!!!!!

So that brings up a dilemma, the HMMWV (stand alone LMM) has the GPS speedometer powered up all the time because it takes too long to boot and find the satellites, can be a 1/2 mile or so, no big deal as it only pulls about 50-75mA.

But if not going to be used for several weeks I expected to turn off the battery switch, what makes this worse is with the HMMWV as far as the stand alone harness is concerned there is no acc, in fact when looking at live data it shows accessory power off, so if I ever loose the "learn" in the TCCM I will have to pull it and install it in the 1 ton, or rewire the stand alone harness,,

geez, this is exhausting!!

The guy in the video mentioned having dead batteries, this would go along with the donor TCCM not working as it sat for months with all the battery cables cut by the fire dept. before it was sold at auction, but evidently it can hold the "learn" for at least a short period without battery power, I wonder if anyone knows how long that is?

But again dndj you are the MAN!!
 
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dndj

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Glad it worked out. :) One other option would be to use a Tech2 to initiate the TCCM relearn without having to pull it from the truck. My Tech2 is a chinese clone btw, works just fine so far no issues, but my LB7 doesn't have a TCCM relearn. GM must have changed something after the GMT-800 trucks.
 

clrussell

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Sep 23, 2013
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Dumb question.. why not swap to a Manuel transfer case?

Youd be done twice already. I mean push button is cool. Less wires is more cool
 

Mogman

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Dumb question.. why not swap to a Manuel transfer case?

Youd be done twice already. I mean push button is cool. Less wires is more cool
Don't need to now, the shift on the fly is very attractive for sand and it's what I had, (as long as you shift before you get into the bad stuff) if I had it all to do over again I would probably go with a manual case, but also as you said push button is cool.
I will just have to change my plan from using the battery switch (every vehicle still needs one!!) to using a battery maintainer.
 

clrussell

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Put the ecm/Tom/tccm on a constant power from
The batteries ( or whatever you want to have memory) then put a switch on the rest of the rig.

or if the only thing you’re concerned about is the gpsspeed, put it on a switch and leave the rest be. ?
 

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