Gmc sierra 2020

[s3eedald]

I orderd an ecm exchange for my gmc sierra 2020 5.3 6l80 also I am willing to get a custom tune but the tcm is locked and I wanted to be tuned. Any Ideas how I can do that .

Thank you!

[tunerpro]

6L80 TCMs are not "locked". If you can't read it, you should contact support for assistance.

If you have an 8 or 10 speed, they use the T93 transmission controller which isn't supported.

[s3eedald]

It is not locked but you can not read it in the newer models

[BPella]

I have the Chevy 2019 Silverado LD with the 5.3 and 6L80 transmission. This combination is the "old" style (before TCM lock) and both the ECM and TCM is not locked. I have just made adjustments to mine. GMC, as far as I know is still using the same old style ECM and TCM for the for the 2020 5.3/6L80 and if you have the 8 speed or 10 speed then it is the new style locked TCM. It takes 4 credits to write both the ECM and TCM on the 5.3/6L80 combination ( just purchased them, $200). My old 2000 Silverado only took 2 and they were assigned to that truck. I hope this helps.