Originally Posted by Kirk@VectorMotorsports
Oil life is partially monitored in the ECM. If you swap ECM’s you have to re-program the remaining oil life into the new one if you want this feature to remain accurate. Re-flashing the calibration does not change the oil life feature. It gets the mileage reading from the IPC (instrument panel cluster).
the mileage is partially stored in the ECM for the OLMS. if it wasnt, then when you pulled the battery, you would lose your readings for the
OLMS. once again, it comes down to a warranty issue, IE driving OVER the OLMS "change oil" for 5,000 miles then resetting it after a change as if you did it when you were supposed to. While its what we call a "coarse" odometer value (a value used purely for calculations and not as accurate as the "fine" odo display on the IPC) it IS an Odometer none the less that HAS been used in warranty disputes for customer neglect.
the ECM retains the oil life reading (and the coarse odometer) even if you swap it into a vehicle with MORE miles on it. How would this "theory" work since the same ECM is used in the G6 (08+ 3.5L) where the odometer is stored in the BCM not the IPC....