Do you have any warning lights on or error messages coming or is it just the odometer flashing without any other visible reason or fault? And is it flashing always, or is it a random fault?
CAN - is something like computer network in your car. All the control units communicate through it (ECU, immobilisers, body computer, A/C, navigation....)
Flashing odometer is not an error message, so it cant be deleted, you must remove the cause why it is flashing.
When you turn the ignition on, your car checks all the devices that are connected by CAN. Basically the body computer asks all devices "who are you?", "what you do?", "are you ok?"
If the odometer starts flashing, it means that your computer couldn't finish this initial check, meaning some device in the network is unknown or doesn't communicate as expected. IT may have many reasons, the most basic one is the battery is on the way out and its voltage is not sufficient to finish the check before starting the engine. Other cause may be new device in the CAN that is not recognized, for example if you change your radio to a navigation unit. I had odo flashing when I changed the window switches in drivers door for ones from a breaker. They worked, but the body computer knew they don't belong to this car. Have you changed something recently on your car?
But if your battery is ok and there are no other warnings and everything works, I think you need to have the car checked on the examiner. Not just a cable and some software erasing error messages, it should be Fiat Alfa examiner able to speak to every ECU in the car and self diagnose them.
And last option is you have no faults, just Alfa electronics is playing with you.
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