Quote Originally Posted by ronniejoe
The PCM or Powertrain Control Module controls both the engine and the transmission (and senses engagement of the front differential). Therefore, it controls the entire powertrain of the vehicle. It's one box. There is no ECU or ECM separate from the PCM.
I didn't know that, thanks!! For some reason I thought there were two computers in play. So, when you upgrade to a Heath or other computer, it's the PCM you are upgrading?

This begs the question, if the PCM is not getting speed from the VSSB as stated above, where does it get it from? I'd think it would care for management of the transmission, cruise, etc.

Art.