TRNW-2: 6t40 techm dead apparently

[Fred Whitaker]

 I have to agree with Reggie. P0601 says internal control module problem.
________________________________
From: trnw2-bounces at trnw.net <trnw2-bounces at trnw.net> on behalf of Reggie Smith via trnw2 <trnw2 at trnw.net>
Sent: Wednesday, July 16, 2025 12:11 PM
To: Steve Everett <severett61 at gmail.com>; Technical Discussion Forum <trnw2 at trnw.net>
Subject: Re: TRNW-2: 6t40 techm dead apparently

With the P0601 what's to say the program is not corrupt in the original TCM?

Reggie Smith

Smith's Transmission Service

5615 Indian Trail

Thomaston GA 30286

Shop 706-647-9199

Cell 706-741-3117

shftless1@<mailto:shftless1 at windstream.net>gmail.com<http://gmail.com>



On Wed, Jul 16, 2025 at 9:18 AM Steve Everett via trnw2 <trnw2 at trnw.net<mailto:trnw2 at trnw.net>> wrote:
   it had a p0601 before was the main reason we were replacing the techm,  I wondered about a correlation between the two,  but haven't had time to do a deep dive into it , as I've got units to build and there is no diag guy here to help me

   Steve

On Wed, Jul 16, 2025 at 9:08 AM <jbockus at hiwaay.net<mailto:jbockus at hiwaay.net>> wrote:
Did it happen to have this code before rebuild? I would start by
checking the power and grounds going to the TEHCM, I've had a few bad
connectors and wires.

On 2025-07-16 7:57 am, Steve Everett via trnw2 wrote:
> Correct,  but I suppose if he damaged the harness somewhere that may
> have bricked the techm when he first cranked it ?
>
>   Steve
>
> On Wed, Jul 16, 2025 at 8:55 AM Justin Merritt
> <justincmerritt5 at gmail.com<mailto:justincmerritt5 at gmail.com>> wrote:
>
>> I re read your original post.  If i understand right, you hooked
>> your hp tuner back up directly to the transmission.  If so, that
>> would bypass all other data lines that may or may not be
>> interfering.
>>
>> Justin
>>
>> On Wed, Jul 16, 2025 at 7:53 AM Steve Everett
>> <severett61 at gmail.com<mailto:severett61 at gmail.com>> wrote:
>>
>> I'll mention it ,  I would like for it to be something like that,
>> as it is now I'm wondering if I inadvertently did something wrong ?
>> but I've done this dozens of times and never had this happen before
>> ,  its just puzzling
>>
>> Steve
>>
>> On Wed, Jul 16, 2025 at 8:48 AM Justin Merritt
>> <justincmerritt5 at gmail.com<mailto:justincmerritt5 at gmail.com>> wrote:
>>
>> Look at your data line communication routing.  Years ago my R&R guy
>> messed up the plug to the electric power steering rack on an equinox
>> 6t40 and the transmission would randomly loose communication.  No
>> crank no communication with scanner was our problem.
>>
>> Justin
>>
>> On Wed, Jul 16, 2025 at 7:44 AM Steve Everett via trnw2
>> <trnw2 at trnw.net<mailto:trnw2 at trnw.net>> wrote:
>>
>> Okay guys,
>> I have no idea what happened, but I may have bricked
>> my first techm ?  although I don't see how ?  I was cloning a techm
>> using hp tuners, like I've done dozens of times, doing it on the
>> bench, we ordered a new GM techm I downloaded the software off the
>> old one, and then re-uploaded the program onto the new tech, the
>> original was from a 2017 vehicle,  the last 4 digits of the part
>> number matched the one we got from from WIT, it was a new GM in a GM
>> box , never opened,  the new techm accepted the software and
>> transfer was complete,  finished the unit, RnR guy installed it,
>> cranked it up and it threw a U0101 code,  try to communicate and it
>> wouldn't , no response, hooked my HP tuners up to the unit,  no
>> response ?
>>
>> Never had this happen before ,  anyone got any ideas ?
>>
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>> TRNW Inc., 2825 Walnut Terrace, Modesto, CA 95355
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