TCC suddenly stopped locking up.

[GPatrick]

The information online is conflicting (no surprise), but TCC Lockup commands have either a minimum engine temperature and/or minimum transmission line temperature to activate lockup. So your observed line temperature of 84°F may be correct or it may require an engine coolant temperature of 150°F or 180°F depending on what you read. Here's one example: https://ls1tech.com/forums/automatic...ckup-temp.html

There are some examples I found where driving on a cold day the TCC would be "locked" and then unlock as temperatures drop and these were on unmodified factory systems.

I don't know what logic Holley uses, but you could try to contact technical support and ask what specific engine or transmission temperatures are used in their system to allow Lockup. You datalogs indeed show that TCC Lockup is never commanded and I can't find any settings in the EFI software that allow a user to change those temperatures.

[TraviZ28]

Terminator X file here:
https://www.dropbox.com/s/xor68571ew...1%29.terx?dl=0

Two datalogs displaying the issue:
https://www.dropbox.com/s/8r0qdbu1lj...-0236.dlz?dl=0
https://www.dropbox.com/s/2oxv60fad4...-0237.dlz?dl=0

Thank you for taking a look. Any advice is well received.

[Rdf1]

Got a GCF tune and a datalog of the issue happening?

[Danny Cabral]

Maybe something in these forum threads will give you a clue:
https://forums.holley.com/forum/holl...358-tcc-lockup (Related Forum Thread)
https://forums.holley.com/forum/holl...591-tcc-lockup (Related Forum Thread)

[TraviZ28]

GM 4L60E. A friend told me his TCC isn't locking up, or when it does, he said it's only when Line Temp exceeds 84°F (unsure of relevance). I've verified in datalogs that he's meeting minimum speeds and TPS to lock it, minimum RPM definitely exceeded, right gear (4th). Is there anything else I may be missing that would prevent it from locking? Datalogs show TCC Duty Cycle at 0% always, but it used to work normally a few weeks ago in previous datalogs.