C2 mileage

[Jack000]

Replaced battery on c2 last night and the milage has gone back to 00000 and does every time you start back up any thoughts it's a 2005

[GiveMeABreak]

The mileage is stored in several places - a small EEPROM chip in the instrument display ECU and the BSI. When a chip gets to end of life it may fail to write the data back to memory when you switch the ignition off and therefore resets. The data should also be stored in the BSI to help prevent tampering - so if either module is replaced with another module, the one with the highest mileage updates the other system to prevent lower mileages recorded by replacing a component.

I suspect your correct mileage is being retained in the BSI and your dashboard module is faulty. If you replaced it with either a new one or a second hand one that works - whichever has the highest mileage (your BSI or the replacement instrument panel ECU) will become the new mileage for the car.

I'm not sure what sort of mileage you have actually done, but consider that the odometer is updating every time you drive a mile - but if the chip is faulty, as soon as it loses power and tries to write the data to the chip it may not be able to and therefore resets back to zero.

[wheeler]

I would do a diagnostics check with diagbox & see if the original mileage is still stored in the BSI (bear in mind it will be in kilometres). This would confirm the car still knows its real mileage before replacing the instrument panel.