just an update - i think i am stuck for now
wanted to flash the ecm with a new operating system.
Connected to the TechLineConnect (soccessor to the retired TIS2Web)... but when i entered the Silverado VIN i got all the info except possibility to download because the vin entered did not match the
actual VIN of the van. Changed the VIN with HPT in the ECM to match the Silverado. HPT reported that it had changed. But when connected back to the TLC i got the same error of a VIN mismatch.
So probably the TLC reads not only ECM VIN but also BCM and other modules and does not allow to flash with not matched VIN numbers.
Funny is that my 6L80 transmission came out of a 2009 Hummer H2 and it did not report he H2 VIN
Please any idea? Is it possible to get the Silverado ECM software (main operating system) as a binary file?