Oh and anyone here know anything about fixing Cars?...

Kind of an important question... My Mom has a 2020 Chevrolet Equinox... And we was going to Walmart earlier and all of a sudden the Check Engine light came on and it said "Engine Power Reduced" and it started going really slow... Well luckily the Mechanic Garage she goes to is on the way to Walmart so we made it there Coasting in... And they Plugged it up to their Computer and said it was a "Software Issue" and fixed it but said it STILL could be a Fuel Pump Issue... And gave her an appointment to come back in a few days so they could check it again... But we left and went to Walmart and back home and it was back to normal the whole time... But do any of you know if it really probably was a Software Issue or the Fuel Pump? I mean she will find out when she goes back to her Mechanic in a few days... But I was just curious to see if anyone on here could tell me anything?... Thanks in advance ❤❤