Everything's OK.
FIAT cars are knows for this. They need specific hardware (CAN pinout and/or proper "termination" - resistors or not, don't remember technicalities) and software to read parameters correctly, run diagnostic tests, reset "learning" functions etc.
Cheap, universal readers will not work or only read and clear error codes, maybe.
Fixing your car is not about erasing codes! You need more.
The same is true for computer (PC or smartphone) diagnostic programs, "universal" ones. They will not read properly engine parameters, only errors at best.
Classic setup for Fiat is: hardware like ELM327 and FES/
MES (Multi ECU Scan) soft for your PC computer, laptop.
To add more confusion,
MES itself is very specific (weird) and will not work with just any "ELM"-like interface (due to communication style/format, "AT commands" - again, technical details, discussed on official
MES forum). Make sure seller (on eBay for example) states clearly, that this particular device is suitable for Fiats.
So, both hardware and software must be FIAT friendly. That's the message here.
PS
To connect with all modules (engine, abs, body computer, airbag and so on), you need device with CAN lines switch or adapters (they are colored, green, yellow for example), details on
MES website.
Example. My setup. Classic cable interface + adapters (will cover all or most of the car modules). The same but wireless (bluetooth) version. Third (don't remember the name, no sticker, but it's also tweaked "for FIAT" and there is a switch instead of adapters).
To make it (
MES) work you may need to install some drivers (in Windows system). Physically it's a USB (or BT wireless), but software (
MES) thinks or wants an old classic serial port ("COM") commands. Drivers make that translation (turn USB into fake, dummy COM port).