Conditions for Setting the DTC: P0606
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 detects that the TAC system has a process sequence error, clock error or processor is not operating correctly. Each test runs in 18.5 milliseconds. DTC sets after 200 milliseconds that a fault is detected.