2004 LB7 Auto TCM read failure

[yonson]

I tried reading out a friends 2004 LB7 and using both 3.6 and 3.7 Beta I get a read or timeout error when trying to read the TCM this happens when trying to do a read entire on the ECM/TCM together or attempting to read the TCM separately, is this a known issue or could he have some kind of mechanical issue causing this?

[mecanicman]

There is an issue that has never been addressed. The work around is to unplug tcm.

[yonson]

Interesting, so the TCM can't be calibrated on those? The ECM reads fine, however the file is quite small (less than 200kb).

[mecanicman]

I don't know if its an o/s based thing or what problem is. Sometimes it works, sometimes it does not. I have contacted support about it on a few occasions and they always tell me there is no problem so I gave up.

[yonson]

Thanks again, I was just concerned when the file was only 139kb, but everything seems to have worked fine.

[Gofastman]

Not sure if it applies to TCMs, but my truck won't do anything unless I disconnect the aftermarket radio module. It screws with the data line when trying to read/write. Just a thought, although mine is an LLY. Also seems like mine has failed on writing the TCM with a combo ECM/TCM before, but it worked on a second try. Not sure if that would help you any.

[Kadams87]

I have success on the LLY by unplugging the ECM after it reads during the 15 second wait for the next module. Reads the TCM every time when I do that. Even on the bench flash harness

[mymonte666]

Want to trade issues? On mine i can't read the pcm, but i can read the tcm just fine. I'm about to put the computer in the microwave. The only reason why i got hp is the duramax, but it it doesn't seem to work.