PCM - How does it determine which tables to use?

[Cyclone Chris]

As far as the tranny goes, how does the PCM determine which table it picks? When does Performance, Normal and Cruise come into play?

I was tuning my friends tranny and he didn't like the fact that the car jerked forward so much while he was just cruising (Sunday Driving) He did however want that forward motion jerk when he was doing some spirited driving. Is there any way to adjust this?

[jimmyblue]

You have to know which car, whether it has a trans
mode button (Tow/Haul, or "Sport"). If not then you
can forget about the "Performance" tables. Cruise is
pretty obvious, Hot is trans fluid overtemp, I see a
trans overtemp set/clear pair in the Transmission
Diagnostics that's 279F (2002 F-body). Get a trans
cooler and stay the hell away from that. Leaves you
the Normal settings, for normal operation. Adjust the
shift pressures in the lower-torque range to get a
softer shift, realize that if you have messed around
the shift time goals then the trans will learn toward
shorter times by more pressure even if the goal is
impossible to meet, ending up at full pressure shifts
in places you might prefer comfort. Maybe allow it
a more leisurely time at TPS below 25%-ish, or zero
the times and adjust the pressures to suit (at least
that will stay put, and not drift around on you with
the weather). If you find a noticeable dependence on
trans temp / driving history then you may need to
get into the upshift / downshift modifiers to flatten
out the "feel" across fluid temp but I'd start with the
base shift pressure tables.