Remote Start Troubleshooting

DaveO9 said:

An important discovery today - my remote start woes ARE related to my non-original t-case control module. We were on vacation over Thanksgiving week (not in the Tahoe) and I had a brainstorm: might as well try and swap back in the original control module to see if it changed anything. Got back last night and today I did the quick swap. Started right up with remote start. Tried it twice just to be sure. Swapped them back and not working again. So that's the problem, now to correct it....

I did the relearn procedure using my Tech 2 - that worked fine, but still no RS. Checked for any DTCs in the transfer case section of the Tech 2 - nothing. The only thing that seems amiss is the VIN code for the module obviously doesn't match the truck. So I'm guessing that is a trip to the dealer? I'm not sure I'm up for a software subscription and trying to get an old win 10 or XP computer up to the task so I can use the Tech 2 as a pass-through. Or is there a simpler method?

General agreement that correcting the VIN in the module will solve the problem? One thing that gives me pause is earlier in this thread, @Tozan confirmed that he did NOT have to reprogram the TCCM with correct VIN after he did the same swap as me (swap 2-speed t-case from 1-speed), and he still has working remote start. I don't know why mine is acting different, could be a programming change between his '11 and my '13.

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well it may not be that simple, I think rather the BCM needs to be programmed for it to see the module correctly or perhaps both.
which means you might have to request a specific calibration from techline/sps if it doesn't work from just letting it update thru sps.
I tried something similar on the Silverado I bought a upgraded radio module with built in nav to upgrade it from onstar nav, added everything needed, erased the old vin on the radio module and it worked, but it wasn't programmed to the vin correctly so I went and did the sps programming and it reverted it back to onstar nav so after some digging around I discovered that I would have to request a specific calibration to enable it thru sps but at that point I had already went with a different radio module and just let it be.

swathdiver said:

I have a modern laptop with Windows 10 and programmed a module recently with an MDI through ACDelco. I think you proved that there are minor differences between your truck and Tozan's with regards to module/programming.

How the 14-bolt axle doing?

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Thanks! 14-bolt doing great. No issues so far, except that I replaced my rear calipers not long after the swap. The old ones were creaking a lot. Replacement solved it.

I'm hoping to use my Tech 2 as a pass-through, as I don't have an MDI. Do you know the current status of that? I found a 2020-ish video last night that made it sound like GM canceled it, but then restarted it. I need to do some more research.

Doubeleive said:

well it may not be that simple, I think rather the BCM needs to be programmed for it to see the module correctly or perhaps both.
which means you might have to request a specific calibration from techline/sps if it doesn't work from just letting it update thru sps.
I tried something similar on the Silverado I bought a upgraded radio module with built in nav to upgrade it from onstar nav, added everything needed, erased the old vin on the radio module and it worked, but it wasn't programmed to the vin correctly so I went and did the sps programming and it reverted it back to onstar nav so after some digging around I discovered that I would have to request a specific calibration to enable it thru sps but at that point I had already went with a different radio module and just let it be.

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Thanks. So are you saying that due to my VIN coding, the BCM would expect only a single-speed module and even if the VIN in the TCCM was correct, it still wouldn't allow it? (In other words, reprogramming a new single speed module would work fine, but the swap to a 2-speed is what it doesn't like?) Man, I hope it isn't that complicated, but we'll see. I guess the only thing I can do is try and see what happens. $45 for a 24-month subscription isn't that bad. I'm just hoping I can get my Tech 2 to work as a pass-thru and can use our current Win 11 laptop.

Here's the video that makes me believe I should be able to use the Tech2 as a Pass-thru:

DaveO9 said:

Here's the video that makes me believe I should be able to use the Tech2 as a Pass-thru:

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the only catch here that he totally does not even mention is after you have paid the $45 vin charge at that point it will give you a button to install the techline software.
it is important that before you even start.
1. open the browser as administrator
2. open any links it gives as administrator
3. open anything it wants you to as administrator
if you do not you will have a hell of a time and even doing the above it make take multiple tries to get everything installed
it will install a whole bunch of stuff, figure a couple hours at least just to get everything installed and updated
this may include restarting the pc over and over and repeating steps until it finally installs everything it needs
otherwise it will just give you errors and will not work
once it is fully installed and up to date it should go smooth.
the new software installs multiple programs including tech2win, sps and gds2 even if you never use it, it's a full package and the only part that will work in the end is what you paid for.

DaveO9 said:

Here's the video that makes me believe I should be able to use the Tech2 as a Pass-thru:

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That's awesome. I didn't know that they made the Tech-2 available again to use.

swathdiver said:

That's awesome. I didn't know that they made the Tech-2 available again to use.

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it's always been able to be used that way (j2534) as far as I know, they just changed the java interface/virtual machine
you just select j2534 device instead of tech2, then on a following page it list's supported devices.
this is in regards to programming modules, diagnostics is likely different I don't know I am not paying there $1200 fee to find out.

Doubeleive said:

it's always been able to be used that way (j2534) as far as I know, they just changed the java interface/virtual machine
you just select j2534 device instead of tech2, then on a following page it list's supported devices.
this is in regards to programming modules, diagnostics is likely different I don't know I am not paying there $1200 fee to find out.

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I remember a time a few years ago when they sunset the Tech-2 and some guys got to use it by calling and getting special access to the old site. One fella on here whose name escapes me documented this pretty thoroughly. Anyhow, I'm glad we can use our Tech-2s and yes, not paying the $64 fee to use GDS2 for 3 days when I can use the Tech-2.

swathdiver said:

I remember a time a few years ago when they sunset the Tech-2 and some guys got to use it by calling and getting special access to the old site. One fella on here whose name escapes me documented this pretty thoroughly. Anyhow, I'm glad we can use our Tech-2s and yes, not paying the $64 fee to use GDS2 for 3 days when I can use the Tech-2.

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That's what I understood from reading other threads here and other forums. I'll report back after I've given it a go. Or more likely, come back here with more questions.

I believe the only thing gm allows you to do is flash software the vin is tied to. in other words like his radio. gm looks up the latest radio software for the module his vin code came with and flashed the software. it doesn't care enough to look at the hardware itself and it can't be undone. so it basically loaded the old software back into his new hardware.

since the hardware wasn't the same, it's honestly lucky it didn't brick the whole thing. or atleast just fail the install. with these modules it's more like flashing base firmware than just software.

I don't believe you can flash a different software thru gm than your vehicle comes with. so if you're truck didn't come with that t-case, it will try and write the single speed software into it. what that does would only be a guess.


it's a shame too, cause the older cars like my 08 c6 I can hook the tech 2 up, and walk thru bcm setup on the screen and tell it what options the car came with. like if you have active suspension and want to put normal shocks on it. instead of faking with resistors, you just use the tech 1 and uncheck the box for z55 option. a few people have even added it to cars that didn't have it. Just go in and enable it. no flashing needed.

it seems they removed that from our newer trucks.

I don't know of anything that could make changes to non ecm software and flash it back into individual modules. be nice if we could.


if you do want to flash gm software without all the hackery and adding sketchy software to your laptop. I found the 140$ OBDxpro gt to be able to do it as a pass thru without any issues. I didn't even try using my clone tech 2. maybe if it was legitimate gm one I would have. but eh. that's and I needed to update a module on my newer gm that the old tech 2 can't access.


I didn't really read thru the thread. is it a fault code from the new t case that's keeping it from auto start? if so, the other work around is if it's an option you might be able to use hptuners to disable that fault code reporting so that it doesn't set and prevent auto start.


I don't know forsure that would work, just a thought since I've used it to disable codes from few different sensors before.

j91z28d1 said:

I believe the only thing gm allows you to do is flash software the vin is tied to. in other words like his radio. gm looks up the latest radio software for the module his vin code came with and flashed the software. it doesn't care enough to look at the hardware itself and it can't be undone. so it basically loaded the old software back into his new hardware.

since the hardware wasn't the same, it's honestly lucky it didn't brick the whole thing. or atleast just fail the install. with these modules it's more like flashing base firmware than just software.

I don't believe you can flash a different software thru gm than your vehicle comes with. so if you're truck didn't come with that t-case, it will try and write the single speed software into it. what that does would only be a guess.


it's a shame too, cause the older cars like my 08 c6 I can hook the tech 2 up, and walk thru bcm setup on the screen and tell it what options the car came with. like if you have active suspension and want to put normal shocks on it. instead of faking with resistors, you just use the tech 1 and uncheck the box for z55 option. a few people have even added it to cars that didn't have it. Just go in and enable it. no flashing needed.

it seems they removed that from our newer trucks.

I don't know of anything that could make changes to non ecm software and flash it back into individual modules. be nice if we could.


if you do want to flash gm software without all the hackery and adding sketchy software to your laptop. I found the 140$ OBDxpro gt to be able to do it as a pass thru without any issues. I didn't even try using my clone tech 2. maybe if it was legitimate gm one I would have. but eh. that's and I needed to update a module on my newer gm that the old tech 2 can't access.


I didn't really read thru the thread. is it a fault code from the new t case that's keeping it from auto start? if so, the other work around is if it's an option you might be able to use hptuners to disable that fault code reporting so that it doesn't set and prevent auto start.


I don't know forsure that would work, just a thought since I've used it to disable codes from few different sensors before.

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gm makes and has calibrations for "upgrades" you just have to message with them and tell them what you are trying to do, you need a paid vin of course and the part number of the module being added.
obviously they made these with different trim levels, so all they have to do is edit the calibration file they provide (upon request) to work with your vin.
all they have to do is look up the part number being added, find the associated calibration file. attach your vin to that file and save it.
then they just give you the calibration file number that you enter into sps to program your vehicle
that's my basic assumption of how that works, I do not know if they charge "extra" for that or not.
I know it can be done because there are gm service bulletins on "how to" that have been provided to dealers when dealing with upgrades
I didn't know this until after I had tried the radio upgrade and started looking into why it didn't work like I expected it to and that point I just said f-it I already was past doing it and made something else work.