Condition 1
WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
The PCM commands 1st gear with the transmission OSS 100 RPM or more and the gear ratio indicates 4th gear, 0.65:1 to 0.75:1, for 1 second.