The RCDLR is where I would look. I had a friend who bought a 2008 Chevy Cobalt with the TPMS light on and was told that the light would NEVER turn off. Also the tire pressures were displayed as (--) on the Driver information center (DIC). I used my DS708 to change the tire loading class and pressure settings from the door placard then performed the relearn using the scan tool initiation method. The light is now off. This issue caused by disconnecting the battery or a low power condition.