Q: Traction Control Fail light on

While this code can be a illuminated for a number of reasons, you are correct that it has to do with servicing the stabilizer system. This light is actually a common one, and the repairs I have seen involve reprogramming the Transfer Case Control Module (TCCM) and replacing the transfer case encoder motor. It must be noted as well that the TCF light appearing is actually a common symptom in the model and year of your particular Hummer. Unfortunately, without more information I am unable to give a proper diagnosis without actually seeing the vehicle. I would highly recommend enlisting the assistance of a certified mechanic so they can give an accurate reason for your Hummer’s Traction Control Fail light.