6l90e issues

[dtes]

i have a 6l90 that on first start up will change up the gears just fine to 4th gear, as soon as it hits 4th it won?t down shift.
Anyone come across this before ?
Is it possible to read dtc?s with hp tuners ?

[87skier]

i have a 6l90 that on first start up will change up the gears just fine to 4th gear, as soon as it hits 4th it won?t down shift.
Anyone come across this before ?
Is it possible to read dtc?s with hp tuners ?

Open VCM scanner, click Vehicle and choose Diagnostics & Info. Choose read DTC's.

Transmission could be going into limp mode. It typically chooses a gear between 1-3 or 4-6 depending on when it occurs.