Hi!!! I am new to the forum as I have a lovely little Fiat Panda 1.2 which I love, but my husband (he's a mechanic) truly HATES!!
It would not start this morning and after looking up all sorts, I Googled "Fiat Key Code", and got some VERY helpful info regarding removing the battery and starting again. Hubby is still charging the battery, so I don't yet know if it works, but as you guys are so incredibly helpful, I thought I'd join up.
Also, although we live in France, I do not read French very well ('im indoors is even worse) and the manual is all in French. Having a forum is going to be a massive help - I hope!

Welcome to the forum

I've added the Panda prefix to your thread to attract the right audience
How can a mechanic hate the Panda though, it's about as simple as it gets! I presume the issue you're having is that the CODE light is staying illuminated on the dash?
Btw, check the downloads section for an English manual

Hi. And welcome

What kind of panda is it ?
.. year and spec: trim level.

Charlie 2004 1.1 Active
2014 TA lounge

Please explain how it behaved when it would not start. Flat battery - slow starter? Fast starter but not firing up? etc?

Spinning starter will happen when the ECU cannot see the ignition key chip code. Have you tried the spare ignition key? Also try removing the key turning it 180 degrees and trying again. This moves the code chip relative to the antenna and can be enough to wake up the system.

If that's no good, suspect the immobiliser antenna at the ignition lock. Easy enough to change after removing the plastic covers. The covers have four annoying screws best replaced with socket heads and might need washers to cover cracked plastic. The clips are tight around the steering wheel so it can need persuading.