Theory of operation: A battery backed RAM
(Random Access Memory) is used to maintain some
learned values. When the battery B(+) is disconnected,
the memory is lost. When the B(+) is restored,
this memory loss is detected by the TCM.
The code is set and the learned values are initialized
to known constants or previously learned values
from EEPROM (Electronic Erasable Programmable
Read Only Memory). This results in the
reinitialization of some parameters.
Transmission Effects: Loss of trouble code data.
Immediate limp-in mode if power is lost while
operating the vehicle. Normal operation is resumed
if the power is restored during the same key start.
Possible causes:
> Battery voltage removed from TCM
> TCM disconnected
> Dead Battery
> Low battery voltage during cranking
> Quick Battery Disconnect by DRBIIIt or MDS
> Bad TCM ground circuit