A pile of codes, all at once...

Delete the thermocouples and cat ECU's and use the Technistrada plug-ins. And o2 sensor extenders to remove the downstream o2 sensors from the exhaust flow. You will probably still get CEL's from the downstream o2's though.

https://technistrada.com/dummy-load-sdl-bypass---not-for-installation-into-vehicles-equipped-with-catalytic-converters

Overall, I would take the time to learn how these systems work.

 

Since no one has the codes for the 5.2 Motronic system, generally we use the 360 codes:

For P1148: Input Signals for Charging Detection (Bank 2)
For P1115: 02 Sensor Heater Circuit (Upstream Catalyst) (Bank 1, Sensor 1)

The F355 and 360 vary somewhat with regards to O2 heater control. The F355 only controls/monitors the heat in pairs (i.e. the precat O2 sensor on both banks or the post cat O2 sensors on both banks), so I'm not really sure what this code signifies for the F355.

There are no diagnostic recommendations for P1148 on the decoding chart, so no clues as to what it means. Low battery or key power voltage?
Live battery voltage is seen on pin 26 of the ECU connector.
Key power is seen on pin 56 and 54. Pin 54 will only get power if injector relay "M" in the passenger footwell is energised. To get the relay to energise with the ECU plug disconnected, you'll have to jumper the relay (pins 30 and 87). Key power comes through the 9 pin plug near the main ECU plug. Pin/wiring defects do occur on this plug from time to time. Check the pins for security/cleanliness. Battery power goes through the 14 pin plug nearby.

 

Doesn't make a lot of sense. I haven't heard of any Technistrada dummy units being faulty (because of their simplicity) and Motronic ECU faults are relatively rare. 1445 and 1149 refer to bank 1 and bank 2 respectively.

Did you clear the codes after you installed the dummy units?

 

@tres55