Originally Posted by cfg83
It seems to me that if I can figure out how the MOVE and WOT/IDLE signal wires behave, I could suppress the cruise control's desire to open the throttle when going uphill.
In looking at the schematic the direction of those signals seems backwards from what I'd expect. Take that as an indication I haven't the first clue what I'm talking about here.
Apply the appropriately-sized grain of salt and reasoned caution as you read what I'm about to type.
Based on general
interface knowledge, here's my off-the-cuff guess:
"MOVE" is a change/step indicator. It indicates when the speed needs to change (or "is changing" if I have the direction backwards). It could be a pulse representing a discrete step, a proportional voltage (unlikely), or a level change that stays until the desired speed is reached. Or something else that hasn't occurred to me yet.
"WOT/IDLE" is the direction for the change. It indicates if the speed needs to go up (towards WOT) or down (towards IDLE), or maybe it indicates which side the error is on (in which case the sense would be reversed).
If the above guesses are right, then the state of the WOT/IDLE line would likely be ignored as long as MOVE wasn't asserted. Also if they're right, then it seems just intercepting the MOVE line and substituting the "all is right with the world" state would cause the cruise control to leave everything alone.
Disclaimer: I know zip about cruise control electronics and even less about Saturns. It would be foolish to rely on any opinions I offer on this subject without testing and verifying. I am not responsible for any damage you do to your cruise control, your car, yourself, any other vehicles, persons, roadways, property, hedges, or small woodland animals.
EDIT for clarification: The above guesses would make a lot more sense if the RASC IN line from the user control went to the CCM and WOT/IDLE and MOVE were inputs
to the PCM. Coming out
of the the PCM as they are is what confuses me -- where does the CCM even get the chance to control anything? Is there another plug/harness on the CCM that connects to the ECU?