Interesting. It seems some need to make an adjustment after battery replacement while some others don't. Do you guys think Toyota/Scion made a change in memory type in the ECUs at a certain time/model year? Maybe from volatile to non-volatile memory? (If you haven't guessed it I studied computer engineering in college for 3 years). Mine is a 2014 and I keep the neg cable disconnected when I'm not driving it much. It doesn't have any start up issue after reconnecting the battery. @IRODGZ88 has a '13 I would guess they made a switch to non-volatile memory between '13 and '14 model years then. Is there anything like a CMOS/BIOS battery in the iQ? Another possibility if there is and it dies, washing the memory like in computers.