This '08 P71's cruise buttons all test good at the PCM connector…

This '08 P71's cruise buttons all test good at the PCM connector, and the SCDS is closed; but cruise still won't engage, including above 40mph. The owner's manual doesn't mention anything disabling cruise other than the OFF button, or driving under 30mph. Will these ABS &/or IC faults cause it to disable? They all re-appear instantly after clearing. Other than no cruise, the car drives perfectly, but I haven't tried to engage ABS. The brake & ABS warning lights are on solid, but occasionally both go out & that fault disappears (without clearing) briefly. The PID for the RESUME button doesn't change state when the button is pressed, and the SCDS PID says NOT SUPPORTED. I don't know that the cruise ever worked on this car, but the wiring to the PCM, and the SCDS are present.

Owner caption February 2021 · Photo 978 of 980