AC compressor coil replacement - can it lead to computer crash?

I have a Peugeot 307 from 2002 (single owner), 3 weeks ago the air conditioning stopped working. My mechanic did replace the compressor coil and AC was back.
I was very happy driving away from the garage but after few minutes the engine stalled and I had to drag it back to the garage. It turns out the car's computer can't communicate with the fuel pump (are there 2 computers there?) And it needs to be taken out and reset – which is quite expensive.
According to the mechanic, the coil replacement isn't related to the computer problem – which is a known Peugeot problem.
Does it sound reasonable? Can a faulty coil or lousy work cause this problem?