12V Memory Saver

If that cleared the odometer, that would be an illegal design. To meet passenger car regulations, the odometer cannot depend on continuous electric power when the car is in storage or taken apart for maintenance and service.

As for the rest, it would be better to ask people with the same design generation as your vehicle, not people with older generations.

 

Thats good to hear. I am not ready to replace my battery yet... 4 years and counting, but its good to know that the lifetime ODO mileage value doesn't get lost. I know its only a number, but I kind of like knowing that number.

 

It’s likely bogus: in my (3rd gen) experience Toyota exaggerates about 7.5%. I doubt they’ve reformed.

 

Not accurate, but it can still contain valuable data and spreadsheet calculations reveal the deltas.