still correcting & being corrected (was adaptive ECU)

[William Magliocco]

Now, Phil adds to the equation...again, I've never
owned a MAC-14 ECU equipped car (MC-2 motor)!

But, on the subject of non-volatile memory, I will
assert that a memory circuit that you can wipe by
simply removing power _IS_ VOLATILE!  The ECU is
simply obtaining some of its power sources straight
from the battery rather than through key switches,
relays, etc.

I've worked on a tremendous amount of electronic gear
with backup batteries (often lithium) used for memory,
product configuration, clock/calendars, ad nauseam. 
It is my understanding that true "non-volatile" memory
means you have memory that won't change state when all
power is removed.  There was one group of products
that had a very stringent method to change said
battery...if you got it wrong, you needed to send the
product back to the factory for reprogramming.

As I stood corrected, my older gasoline powered V-A-G
cars had the simpler ECUs...my thinking did not extend
beyond the 1986 5000 kT sitting outside (with bad
diff), or the '88 VW Fox (hardly a high-tech ECU by
today's standards)...

in that latter case, the ECU was not even able to tell
me when the coolant temp sensor failed in "cold" mode.
Had to diagnose it by the book...cold the car was ok,
but when warm, way too rich with attendant
driveability problems.  The ECU had no diagnostics.  I
think it was all linear ICs inside the box too.  

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