ECU Programming: How to Learn/Calibrate

hello
To my "never-ending story."
Error code 17981 in the mass flow controller's fault memory.
The car starts, but then immediately accelerates to full speed.
"Remanufactured pump installed... car won't start anymore !?!?"
"Get the control unit checked... unfortunately, it's defective (short circuit)."
after the repair, the error is still there .
"Another test of the control unit revealed that 'the software seems to be a bit messed up (you wouldn't believe what can happen...)'."
"I had a new EEPROM and software installed, but it still doesn't work..."
However, there are no more errors in the memory.
I also switched the pump back to the old one (which wasn't actually defective).
What now???
Does the control unit need to be reprogrammed?
It should at least start up once.
Thank you for any advice.

It's likely that the pump is misadjusted. Even a few millimeters can cause the motor to over-rev.